Friday, December 27, 2013

Simple linear Regulator Circuit Diagram

This is Simple linear Regulator Circuit Diagram. Intended for extreme temperature, radiation-hardened environments, this linear supply is capable of supplying 28 Vdc at 125 A from an ac-driven power unit. In operation, power supply output voltage is sensed by the voltage divider consisting of R24 to R28 and fed to one input of a discrete differential amplifier composed of Q13 through Q16. 

The other input of the amplifier is connected to a radiation-hardened zener diode, Dl. Local feedback using R21 and Cl produces gain to phase shift that are independent of individual component parameters, which provides stable operation into the required loads.

Simple linear Regulator Circuit Diagram

Simple linear Regulator Circuit Diagram

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Thursday, December 26, 2013

LDR Based 12V White LED Driver for up to 30 LEDs

While we have now published quite a few LED driver circuits, to date we have not published a design to drive a bunch of high-brightness white LEDs. Such a circuit is now quite desirable as the price of white LEDs has fallen and you can have a handful for not a lot of dollars. However, white LEDs do present a problem because they need a higher drive voltage than monochromatic types such as red, green, orange etc.

30 White LEDs Driver Circuit Diagram

Instead of around 1.8V to 2V or thereabouts, they normally require more than 3V to produce their rated brightness. In fact, if you are driving a bunch of them you need to drive them all at constant current otherwise their individual brightness tends to vary markedly. However, if you only have a 12V supply available, you can only put two or maybe three LEDs in series together with a constant current source and this leads to poor efficiency.

30 White LEDs Driver Circuit Diagram

The approach in this circuit is to boost the 12V supply to something around 21V and this means that we can have groups of five LEDs, each in series with their own current source transistors. The result is a single PC board with the drive circuitry and 30 white LEDs. It can be used for lighting in caravans and recreational vehicles, emergency lighting or whatever application you can think of. Current drain is around 190mA at 12V.

Circuit description

Now let’s have a look at the circuit of Fig.1. It uses just one IC (a 4093 quad NAND Schmitt trigger gate package), a few transistors and diodes, 30 white LEDs and not much else. So where is the familiar boost converter circuit? Answer: there isn’t one or least not one with an inductor switched by a Mosfet. Instead, there is a charge pump inverter, comprising IC1c, transistors Q2 & Q3, Schottky diodes D1 & D2 and a few capacitors. It works as follows:

30 White LEDs Driver Circuit Diagram

IC1c is connected as an inverter oscillator and its running frequency of about 30kHz is determined mainly by the 6.8kΩ resistor between pins 8 & 10 together with the 4.7nF capacitor at pin 8. This produces a rectangular waveform (not quite square but pretty close) at pin 10 to drive complementary switching transistors Q2 & Q3.

The waveform at their commoned emitters drives a diode pump consisting of two 100μF capacitors and Schottky diodes D1 & D2. The waveform generated by the circuit can be seen in the scope photo of Fig.2.

RS flipflop

Oscillator IC1c is controlled by an RS (Reset/Set) flipflop comprising the two NAND gates IC1a & IC1b and this is controlled by pushbutton switches S1 and S2. Normally, this has its pin 4 low and pins 1 & 6 are pulled high via 470kΩ resistors. Momentarily closing S1 (ON) pulls pin 6 low, causing the flipflop to change state so that pin 4 now goes high to enable IC1c which now oscillates at 30kHz.

30 White LEDs Driver Circuit Diagram

The 30kHz waveform produced by transistors Q2 & Q3 drives the diode pump referred to earlier and this develops about 21V to drive the LED columns. Each column of five white LEDs is driven by its own current source transistor which has a 33Ω emitter resistor. The bases of all six current source transistors (Q4-Q9) are driven from pin 4 of IC1b via a 6.8kΩ resistor and clamped to a maximum of +1.2V by diodes D3 & D4.

Subtract the 0.6V between the base and emitter of each transistor and you are left with 0.6V across each 33Ω resistor, thus setting the LED drive current to 18mA. Switching the circuit off is accomplished by pushing the OFF switch, S2. This momentarily pulls pin 1 low to toggle the RS flipflop, thus causing pin 4 to go low. This disables IC1c, Q2 & Q3 and also turns off the current source transistors.

Note that there is an interesting wrinkle to this drive circuit, because there is no On/Off switch. This means that the current source transistors must be turned off otherwise they would continue to draw current from the 12V supply even when the circuit is nominally off. The current path may not be obvious but it is via the boost circuit’s diodes, D1 & D2.

Auto on/off

As well as using the pushbutton switches S1 & S2 to turn the circuit on and off, there is also a facility to automatically turn the circuit on and off depending on ambient light levels. Links L1 & L2 can be used to provide Auto On and Auto Off respectively and these features can be used separately or together.

30 White LEDs Driver Circuit Diagram

An LDR (light dependent resistor) is used to monitor the ambient light level. When light falls upon it, it pulls the base of Q1 low, causing pins 12 & 11 of IC1d to go low and its pin 11 to go high. When darkness falls (or the room lights go out), the process is reversed. Depending on whether you have one or both links connected, you can use the pushbuttons to turn the circuit on and off and have it turn on and/off automatically as well.

Q1 also drives a red high brightness LED (LED1) at very low current, via a 470kΩ resistor. This is a bit of a gimmick but it does have the benefit of showing that this part of the circuit is working, if you have to trouble-shoot it.


Pins 1 & 2, 5 & 6 and 8 & 9 of IC1 on the circuit are all swapped. The PC board overlay diagram is correct.

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Simple Multivoltage Power Supply Circuit Diagram

This dual-polarity, multivoltage power supply circuit diagram can be built for a very small investment. The circuit is built around 78XX and 79XX series i-A voltage regulators, four 3-A diodes, a 24-30-V 2-6-A transformer, and eight filter capacitors.

Multivoltage Power Supply Circuit Diagram

Multivoltage Power Supply Circuit Diagram

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Wednesday, December 25, 2013

Two Wire Temperature Sensor

Remote temperature measurements have to be linked by some sort of cable to the relevant test instrument. Normally, this is a three-core cable: one core for the signal and the other two for the supply lines. If the link is required to be a two-core cable, one of the supply lines and the signal line have to be combined. This is possible with, for instance, temperature sensors LM334 and LM335. However, these devices provide an output that is directly proportional to absolute temperature and this is not always a practical proposition.

Circuit diagram :

Two-Wire Temperature Sensor-Circuit Diagram

Two-Wire Temperature Sensor Circuit Diagram 

If an output signal that is directly proportional to the celsius temperature scale is desired, the present circuit, which uses a Type LM45 sensor, offers a good solution. The LM45 sensor is powered by an alternating voltage, while its out-put is a direct voltage.

The supply to the sensor is provided by a sine-wave generator, based on A 1 and A 2 (see diagram). The alternating volt-age is applied to the signal line in the two-core cable via coupling capacitor C 6 .

The sensor contains a volt-age-doubling rectifier formed by D 1 -D 2 -C 1 -C 2 . This network converts the applied alternating voltage into a direct voltage. Resistor R 2 isolates the output from the load capacitance, while choke L 1 couples the output signal of the sensor to the signal line in the cable. Choke L 1 and capacitor C 2 protect the output against the alternating voltage present on the line.

At the other end of the link, network R 3 -L 2 -C 4 forms a low-pass section that prevents the alternating supply voltage from combining with the sensor out-put. Capacitor C 5 prevents a direct current through R 3 , since this would attenuate the temper-ature-dependent voltage.

The output load should have a high resistance, some 100 kΩ or even higher.  The circuit draws a current of a few mA.

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Simple UPS Power Supply

This circuit is a simple form of the commercial UPS, the circuit provides a constant regulated 5 Volt output and an unregulated 12 Volt supply. In the event of electrical supply line failure the battery takes over, with no spikes on the regulated supply.

 Basic UPS Power Supply-1 


This circuit can be adapted for other regulated and unregulated voltages by using different regulators and batteries. For a 15 Volt regulated supply use two 12 Volt batteries in series and a 7815 regulator. There is a lot of flexibility in this circuit.

TR1 has a primary matched to the local electrical supply which is 240 Volts in the UK. The secondary winding should be rated at least 12 Volts at 2 amp, but can be higher, for example 15 Volts. FS1 is a slow blow type and protects against short circuits on the output, or indeed a faulty cell in a rechargeable battery. LED 1 will light ONLY when the electricity supply is present, with a power failure the LED will go out and output voltage is maintained by the battery. The circuit below simulates a working circuit with mains power applied:

Basic UPS Power Supply-2

Note that in all cases the 5 Volt regulated supply is maintained constantly, whilst the unregulated supply will vary a few volts.

Basic UPS Power Supply-3

Standby Capacity

The ability to maintain the regulated supply with no electrical supply depends on the load taken from the UPS and also the Ampere hour capacity of the battery. If you were using a 7A/h 12 Volt battery and load from the 5 Volt regulator was 0.5 Amp (and no load from the unregulated supply) then the regulated supply would be maintained for around 14 hours. Greater A/h capacity batteries would provide a longer standby time, and vice versa.

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Tuesday, December 24, 2013

Variable Zener Diode Circuit Diagram

The circuit behaves like a zener diode over a large range of voltages. The current passing through the voltage divider R1-R2 is substantially larger than the transistor base current and is in the region of 8 mA. The stabilizing voltage is adjustable over the range 5-45 V by changing the value of R2. The total current drawn by the circuit is variable over the range 15 mA to 50 mA.This value is determined by the maximum dissipation of the zener diode. In the case of a 250 mW device, this is of the order of 50 mA.

Variable Zener Diode Circuit Diagram

Variable Zener Diode Circuit Diagram

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Simple Battery Temperature Sensing Nicad Charger

Simple Battery-Temperature Sensing Nicad Charger. Two simple circuits permit Nicad charging of a battery based on temperature differences between the battery pack and the ambient temperature. This method has the advantage of allowing fast charging because the circuit senses the temperature rise that occurs after charging is complete and the battery under charge is producing heat, not accumulating charge. 

 Battery-Temperature Sensing Nicad Charger Circuit Diagram

Battery-Temperature Sensing Nicad Charger
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Traffic Light Controller

Here the simple traffic light controller which is could be used to educate kids rudiments of traffic light guidelines. The circuit utilizes easily available electronic parts. It generally consists of rectifier diodes (1N4001), a 5V regulator 7805, two timers circuit using IC 555, two relays (5V, single-changeover), three 15W, 230V light bulbs and also several discrete parts.

Traffic Light Controller Circuit diagram :

Mains electrical power is stepped down by transformer X1 to provide a secondary output voltage of 9V, 300 mA – AC. Then the transformer output current is rectified by a full-wave bridge rectifier composed of diodes D1 through D4, filtered by capacitor C1 and also regulated by IC 7805 (IC1).

IC2 is wired as a multivibrator with ‘on’ and ‘off’ periods of about 30 seconds each with the part values determined. Once mains power switch is turned on, pin 3 of IC2 goes high for 30 seconds. This, in turn, energises relay RL1 via transistor T1 and the red bulb (B1) glows through its normally-open (N/O) contact. At the same time, mains power is turned off from the pole of relay RL2. As the ‘on’ time of IC2 ends, a triggers IC3 through C5. IC3 is set up as a monostable with ‘on’ time of about 4 seconds, which indicates pin 3 of IC3 will stay high for this period of time and energise relay RL2 through driver transistor T2. The amber bulb (B2) thus lightings up for 4 seconds.

Immediately after 4-second time period of timer IC3 at pin 3 lapses, relay RL2 de-energises and also the green bulb (B3) lights up for the rest of ‘off’ period of IC2, which is about 26 seconds. The green bulb is turned on through the normally closed (N/C) contacts of relay RL2. So when mains electrical switch is turned on, red light will light up for 30 seconds, amber for 4 seconds and green for 26 seconds.

You can easily build this circuit on a general purpose PCB and enclose in a protected box. The box needs to have sufficient area for installing transformer X1 and also two relays. It could be installed near 230V AC, 50Hz power supply or mounted on the PVC tube applied in assembly of the traffic light box.

Design of the traffic light container box is demonstrated in following image:

A stout cardboard box of 30x15x10cm3 is needed for housing the lights. To make certain durability, work with a 10x45cm2 plywood plate having 1.5 centimeters thickness and also secure onto it three light outlets and the box utilizing nuts and bolts or screws. Make three tubes of thin aluminium sheet, which is easily offered in equipment stores. The inner diameter of aluminium tubes ought to be such that these can well match on the light outlets. Working with a sharp knife, make holes opposite the outlets carefully. Wire the outlets at the back and take the cables out through the PVC tube.

To begin with, fix three 15W light bulbs (B1 through B3) and then press on the tubes. Support the other ends of the tubes in the holes made on the front panel of cardboard box. Sandwich gelatine papers of the three colors in between two sheets of cardboard and fix over the tubes. The visibility of red, amber and also green lights enhances with their installation on the tubular shape.
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Monday, December 23, 2013

Optical technology is tiny particles can be captured

 In order to change this situation, the United States, Illinois, New York University and an optical company scientists, researchers tested a product called "light trap" technology, trying to be more convenient to manipulate carbon nanotubes. Optical technology is tiny particles can be captured using the signal capturing ability to move the signal beam in the signal to follow the movement of the fine particles. Signal can capture tiny particles, so it would be like tweezers to move tiny particles moving folder. The quality of the products offered by the two subcontractors phone boosters are very good.
The most common problem is reported use of micro-cellular phone may display you have five full signal strength. Call directly into voicemail ring. The reason is because the micro cellular behind the idea under the premise of the construction site, to build a miniature battery. The microcell tether recent site, and then take advantage of the Wi-Fi signal, in order to strengthen their reception and transmission bandwidth.
The pursuit of low-cost mobile phone maker has also spawned a number of new business opportunities. The original baseband IC field is Texas Instruments. However, these always attaches great importance to the base price of the domestic mobile phone manufacturers in the industry with handset manufacturers dissatisfaction, a significant loss. Once a suitable alternative suppliers, domestic mobile phone manufacturers immediately anti-Ge. Other suppliers is Taiwans largest IC design company MediaTek. MediaTek low-cost baseband IC quickly captured the mainland market, almost all of the Chinese mobile phone manufacturers, including Asus and BenQ MediaTek customers. After the installation is complete, turn off the circuit breaker or phone boosters, and turn on the power switch. Texas Instruments beat beaten. MediaTek are cashing overflow, MediaTeks report shows, pre-tax income of the U.S. dollar, the Taiwan stock market profits. Most of the mobile phone industry chain manufacturers and performance of domestic mobile phone manufacturers.
Keeping that in mind, rarely introduced new equipment call phone signal booster, market a few years ago. , Phone booster introduced several years ago, but as time goes by, and its technology has been updated. In such a small period of time to introduce mobile phone supercharger technology has improvised a lot of times, this is a cell phone signal amplifier on the market a wide range of reasons.
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Low cost Step down Converter with Wide Input Voltage Range

The circuit described here is mostly aimed at development engineers who are looking for an economical step-down converter which offers a wide input volt- age range. As a rule this type of circuit employs a step-down converter with integrated switching element. However, by using a more discrete solution it is possible to reduce the total cost of the step- down converter, especially when manufacturing in quantity. The TL5001A is a low-cost PWM controller which is ideal for this project.

Low-cost  Step-down Converter with Wide Input

The input voltage range for the step-down converter described here is from 8 V to 30 V, with an output voltage of 5 V and a maximum output current of 1.5 A.

When the input voltage is applied the PWM output of IC1 is enabled, taking one end of the voltage divider formed by R1 and R2 to ground potential. The cur-rent through the voltage divider will then be at most 25 mA: this value is obtained by dividing the maximum input voltage (30 V) minus the saturation voltage of the output driver (2 V) by the total resistance of the voltage divider (1.1 kΩ ). T1 and T3 together form an NPN/PNP driver stage to charge the gate capacitance of P-channel MOSFET T2 as quickly as possible, and then, at the turn-off point, discharge it again.

The base-emitter junction of T3 goes into a conducting state when the PWM output is active and a voltage is dropped across R2. T3 will then also conduct from collector to emitter and the gate capacitance of T2 will be discharged down to about 800 mV. The P-channel MOSFET will then conduct from drain to source. If the open-collector output of the controller is deactivated, a negligibly small current flows through resistor R2 and the base of T1 will be raised to the input voltage level. The base-emitter junction of T1 will then conduct and the gate capacitance of T2 will be charged up to the input voltage level through the collector and emitter of T1. The P-channel MOSFET will then no longer conduct from drain to source. This driver circuit constructed from discrete components is very fast, giving very quick switch-over times.

Diodes D2 and D3 provide voltage limiting for the P-channel MOSFET, whose maximum gate-source voltage is 20 V. If the Zener voltage of diode D2 is exceeded it starts to conduct; when the forward voltage of diode D3 is also exceeded, the two diodes together clamp the gate-source voltage to approximately 19 V.

The switching frequency is set at approximately 100 kHz, which gives a good compromise between efficiency and component size.

Finally, a few notes on component selection. All resistors are 1/16 W, 1 %. Apart from electrolytic C1 all the capacitors are ceramic types. For the two larger values (C2 and C5) the following are used:

C2 is a Murata type GRM21BR71C105KA01 ceramic capacitor, 1 µF, 16 V, X7R, 10 %;

C5 is a Murata type GRM32ER60J476ME20 ceramic capacitor, 47 µF,  6.3 V, X5R, 10 %.

D1 (Fairchild type MBRS340T3) is a 40 V/3 A Schottky diode. Coil L1 is a Würth WE-PD power choke type 744771147, 47 µH, 2.21 A, 75 mΩ.

T1 (BC846) and T3 (BC856) are 60 V, 200 mA, 310 mW complementary bipolar transistors from Vishay.

The TL5001AID (IC1) is a low-cost PWM controller with an open-collector output from Texas Instruments.

Author : Dirk Gehrke Copyright : Elektor

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Sunday, December 22, 2013

Preregulator for Power Supply Circuit Diagram

This SCR pre-regulator keeps the filter capacitor Vc, in a variable output power supply, a few volts above the output voltage V0. The benefits include: less heat dissipated by the pass transistor and therefore small heatsink, cooler operation and higher efficiency, especially at low output voltages. Ql, Rl, R2, Dl and D2 form a constant current source for zener Zl, so that the contribution to the output current is always a few mA (2-3 mA). The Darlington pair Q2, Q3 keeps the SCR off.

Preregulator for Power Supply Circuit Diagram

Preregulator for Power Supply Circuit Diagram

The voltage Vc decreases until Vc = V0 = V at which point the Darlington pair fires the SCR, charging the filter capacitor to a higher voltage VC1 in less than half the period of the input voltage. The component values, shown are for a 0 - 250-V, 3-A power supply.

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Build a Efficient Negative Voltage Regulator Circuit Diagram

How to Build a Efficient Negative Voltage Regulator Circuit Diagram. This simple Efficient Negative Voltage Regulator Circuit Diagram is One v;ay to provide good negative-voltage regulation is with a low-dropout positive-voltage regulator operating from a well-isolated secondary winding of switch-mode circuit transformer. The technique works with any positive-voltage regulator, although highest efficiency occurs with low-dropout types. 

Under all loading conditions, the minimum voltage difference between the regulator ViN and VoUT pins must be at least 1.5 V, the LT1086`s low-dropout voltage. Efficient-negative-voltage-regulator Rating: 7.00/10 (23Votes cast)Category: Power Supply Circuits / AC to DC & DC to DCViews: 3Rank: 5One v;ay to provide good negative-voltage regulation is with a low-dropout positive-voltage regulator operating from a well-isolated secondary winding of switch-mode circuit transformer. 

 Efficient Negative Voltage Regulator Circuit Diagram

Efficient Negative Voltage Regulator Circuit Diagram

The technique works with any positive-voltage regulator, although highest efficiency occurs with low-dropout types. Under all loading conditions, the minimum voltage difference between the regulator ViN and VoUT pins must be at least 1.5 V, the LT1086`s low-dropout voltage.Efficient-negative-voltage-regulatorIf this requirement isn`t met, the output falls out of regulation. 1vo programming resistors, R1 and R2, set the output voltage to 12 V, and the LT1086`s servo the voltage between the output and its adjusting (ADJ) terminals to 1.25 V. 

Capacitor C1 improves ripple rejection, and protection diode D1 eliminates common-load problems. Since a secondary winding is galvanically isolated, a regulator`s 12 V output can be referenced to ground. Therefore, in the case of a negative-voltage output, the positive-voltage terminal of the regulator connects to ground, and the -12 V output comes off the anode of Dl. The ViN terminal floats at 1.5 V or more above ground.
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Power Supply Balance Indicator Circuit Diagram

This circuit uses two comparator pairs from an LM339N quad comparator; one pair drives the yellow positive (+)and negative (-)indicators, the other jointly drives the red warn LED3. The circuit draws its power from the unregulated portion of the power supply. The four comparators get their switching inputs from two parallel resistor-divider strings. Both~strings have their ends tied between the power supply`s positive and negative output terminals. 

The first string, consisting of R4, R5, and R6, divides the input voltage in half, with output taps at 0.5%. The other string, made up of R7, R8, and R9, also divides the input voltage in half, with taps at + lO%. The 0.5% R4/R5/R6 string drives the two comparators controlling the positive and negative indicators (LEDl and LED2). Their inputs are crossed so that LED2 does not fire until the positive supply is at least 0.5% higher than the negative; the positive indicator does not go off until the negative supply is at least 0.5% higher than the positive-in relative levels. 

That overlap permits both LEDs to be on when the two supplies are in 1 % or better balance. The +lOT R7/R8/R9 string drives the other two comparators, which control the warn indicator. If either side of the supply is lO% or more higher than the other, one of the two comparators will switch its output low and light the redLED3the LM339N has opened-collector outputs, allowing such wired OR connections. The inputs are not crossed, as with the other comparator pair, so there is a band in the middle where neither comparators output is low and the LED remains off.

Power Supply Balance Indicator Circuit Diagram

Power Supply Balance Indicator Circuit Diagram

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Saturday, December 21, 2013

Simple Equipment on reminder Circuit Diagram

This is an Equipment on reminder Circuit Diagram. Due to the low duty cycle of flashing LED, the average current drain is 1 mA or less.

Equipment on reminder Circuit Diagram

Equipment on reminder Circuit Diagram

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Datasheet of 24C32

These I2C-compatible electrically erasable pro-grammable memory (EEPROM) devices are orga-nized as 8192x8 bits (M24C64) and 4096x8 bits(M24C32), and operate down to 2.5 V (for the -Wversion of each device), and down to 1.8 V (for the-R version of each device).The M24C64 and M24C32 are available in PlasticDual-in-Line, Plastic Small Outline and Thin ShrinkSmall Outline packages.

Datasheet file: Click here to download 24C32.pdf datasheet.
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Friday, December 20, 2013

Simple Efficient Supply Splitter Circuit Diagram

Simple Efficient Supply Splitter Circuit Diagram. In this application, the Vl-7660 is connected as a voltage splitter. Note that the normal output pin is connected to ground and the normal ground pin is used as the output. The switches that allow the charge pumping are bidirectional; therefore, charge transfer can be performed in reverse. 

The 1-MO resistor is used to avoid start-up problems by forcing the internal regulator on. An application for this circuit would be driving low-voltage, ± 7.5 Vdc, circuits from ± 15 Vdc supplies, or low-voltage logic from 9 to 12 V batteries.

Efficient Supply Splitter Circuit Diagram

Efficient Supply Splitter Circuit Diagram

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40 LED Bicycle Light

The 555 circuit below is a flashing bicycle light powered with four C,D or AA cells (6 volts). Two sets of 20 LEDs will alternately flash at approximately 4.7 cycles per second using RC values shown (4.7K for R1, 150K for R2 and a 1uF capacitor). Time intervals for the two lamps are about 107 milliseconds (T1, upper LEDs) and 104 milliseconds (T2 lower LEDs). Two transistors are used to provide additional current beyond the 200mA limit of the 555 timer.

Circuit  Project: 40 LED Bicycle Light

A single LED is placed in series with the base of the PNP transistor so that the lower 20 LEDs turn off when the 555 output goes high during the T1 time interval. The high output level of the 555 timer is 1.7 volts less than the supply voltage. Adding the LED increases the forward voltage required for the PNP transistor to about 2.7 volts so that the 1.7 volt difference from supply to the output is insufficient to turn on the transistor.

Each LED is supplied with about 20mA of current for a total of 220mA. The circuit should work with additional LEDs up to about 40 for each group, or 81 total. The circuit will also work with fewer LEDs so it could be assembled and tested with just 5 LEDs (two groups of two plus one) before adding the others.
Circuit Source: DIY Electronics Projects
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Thursday, December 19, 2013

Telephone Ringer

If you are lucky enough to have a big house, a large garden, and small children, this project just might interest you. It’s actually a telephone ringer capable of making any mains-powered device work from the ringer of your fixed line. With it, you will be able to control a high-powered siren or horn, as you like, in order to relay and amplify the low-level sound of your telephone (making it audible in a big house or in a large garden)! Alternatively, you can make a lamp light (or an indicator light) and so create a ‘silent ringer’ (helpful when small children are napping).

The other interesting part of this simple and inexpensive project is that it doesn’t require a power supply, contrary to similar items on sales in the shops. Before examining the drawing and understanding the principle involved, it is important to know that the ringer voltage on a fixed telephone line is pretty high. Since Europe and the EU Commission have not yet interfered, the exact value of this voltage and its frequency varies according to the country, but that’s not important here. The line carries direct current whether unoccupied or occupied.

Moreover, no more than a few hundred mAs needs to be stolen from an unoccupied telephone line to make the PSTN exchange believe the line is occupied. Therefore, capacitor C1 has the dual role of insulating this project with respect to direct current present on the line while unoccupied, or while occupied, while also allowing the ringer current to pass. The latter is rectified by D1 and clipped by D2 which makes about 6 V DC available to the C2 terminals when a ringer signal is present.

Telephone Ringer Circuit Diagram

telephone ringer-circuit diagram
This voltage lights LED D3 which only serves as a visual indicator of proper operation as does the LED contained in IC1. This is a high-power photo triac with zero crossing detection from the mains, which allows it to switch the load it controls without generating even the lowest level of noise. This component, that we might just as well call a solid-state relay, was selected because it is comes in the form of a package similar to a TO220, a little bigger, and equipped with four pins. The pinout will not cause confusion because the symbols shown on our diagram are engraved or printed on the packaging. Since this circuit is not yet very common, we need to mention that it’s available from the Conrad Electronics website (

For the purpose of safe operation, the circuit is protected by a GeMOV on the mains side, called Varistor, VDR or SiOV depending on the manufacturer. The model indicated here is generally available. The load will be limited to 2 A, considering the model selected for IC1, which is more than sufficient for the application planned here. Finally, since a number of components in this circuit are connected directly to the mains power supply, the assembly should be placed in a completely insulated housing for obvious safety reasons.
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The expert group is making every effort to enhance the design of the Cell Phone Jammers system

The expert group is making every effort to enhance the design of the Cell Phone Jammers system.
The standard test signal I1: is GsM modulated carrier signal, and its structure in accordance with the GSM signal burst (burst, as burst or short burst. Below) structure, but its all modulation bits (including the burst of part of the training sequence) are directly random or pseudo-random data stream. (5) The standard test signal I2: a standard GSM modulation signal, but with the C1 signal is different from the unexpected part of the training sequence of the standard GSM training sequence, but the burst of data bits (including bits 58 and 59) are random or pseudo-random data stream. Using the same standard RF cable and adapters, including adapters, including the requirements of the GSM bands between the channel loss is less than 0.5dB, loss of value of the difference is less than 0.2dB; DCS frequency band between the loss of each channel is less than 1dB, loss value difference is less than 0.3dB, with characteristic impedance adapter should be within 50 ± 5 ohms. The table will contain the result of quantity computation of Cell Phone Jammers .I use the above principles and interface technology to develop a project: Highway display guidance system. Installed on the highway in front of the LED display shows real-time road vehicle traffic situation and weather and climate conditions, advise and guide the driver, the correct driver. The use of the system to some extent, eliminate a lot of traffic hazards, thereby safeguarding the smooth flow of road safety and peoples lives and property. The system consists of the control center and several display screen. Control center in real time the latest information sent to the display. Building control center communication link with the display terminal, the traditional method of laying fiber optic cable with the cable or the realization, or build a private wireless network allowing wireless. Because of the special nature of the highway, the control center and the distance between the display terminal is usually very far, two programs must invest a lot of money and huge construction effort.
Typically, short message service SMS-based wireless data transmission monitoring and control system for a point to multipoint wireless two-way data communication and remote control system, shown in Figure 1. System control center or command center for data, from computer networks, databases, electronic map and GSM communication interface. The main control center complete the information and data transceiver and finishing: on the one hand, to receive various control points to upload information and data, and put them in the appropriate database and distributed to the appropriate monitoring computer in order to achieve the various monitoring points monitoring and management; another aspect, a computer control center monitors the response issued by the various monitoring points of the control information, and to the information issued to the corresponding control points to achieve the point of monitoring equipment for control purposes.
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Mini Ups System

This circuit provides an uninterrupted  power supply (UPS) to operate 12V, 9V and 5V DC-powered instruments at up to 1A current. The backup battery takes up the load without spikes or delay when the mains power gets interrupted. It can also be used as a workbench power supply that provides 12V, 9V and 5V operating voltages. The circuit immediately disconnects the load when the battery voltage reduces to 10.5V to  prevent deep discharge of the battery.  LED1  indication  is  provided  to  show  the full charge voltage level of the battery. miniature white LEDs (LED2 and  LED3) are used as emergency lamps during power failure at night.

Mini Ups System Circuit diagram:

Mini Ups System Circuit Diagram

A standard step-down transformer provides 12V of AC, which is rectified by diodes D1 and D2. Capacitor C1 provides ripple-free DC to  charge the battery and to the remaining circuit. When the mains power is  on, diode D3 gets forward biased to charge the battery. Resistor R1 limits the charging current. Potentiometer VR1 (10k) with transistor T1 acts as the voltage comparator to indicate the voltage level. VR1 is so adjusted that LED1 is in the ‘off’ mode. When the battery is fully charged, LED1 glows indicating a full voltage level of 12V.

When the mains power fails, diode D3 gets reverse biased and D4 gets forward biased so that the battery can automatically take up the load without any delay. When the battery voltage or  input voltage  alls below 10.5V, a cut-off circuit is used  to prevent deep discharging of the battery. Resistor R3, zener diode  ZD1 (10.5V) and transistor  T2  form  the  cut-off circuit. When the voltage level is above 10.5V, transistor T2 conducts and its base becomes negative (as set by R3, VR2 and ZD1). But when the voltage reduces below  10.5V, the zener diode stops conduction and the base voltage of transistor T2 becomes positive. It goes into the ‘cut-off’ mode and prevents the current in the output stage. Preset VR2 (22k) adjusts the voltage below 0.6V to make T2 work if the voltage is above 10.5V.

When power from the mains is available, all output voltages—12V, 9V and 5V—are ready to run the load. On the other hand, when the mains  power is down, output  volt-ages can run the load only when the  battery is fully charged (as indicated by LED1). For the partially charged battery, only 9V and 5V are available. Also, no output is available when the voltage goes below 10.5V. If battery voltage varies between 10.5V and  13V, output at terminal A may also vary between 10.5V and 12V, when the UPS system is in battery mode.

Outputs at points B and C provide 9V and 5V, respectively, through regulator ICs (IC1 and IC2), while output A provides 12V through the zener diode. The emergency lamp uses two ultra-bright white LEDs (LED2 and LED3) with current limiting resistors R5 and R6. The lamp can be manually switched ‘on’ and ‘off’ by S1. The circuit is assembled on a general purpose PCB. There is adequate space between the components to avoid overlapping. heat sinks for transistor T2 and regulator ICs (7809 and 7805) to dissipate heat are used.

The positive and negative rails should be strong enough to handle high current. Before connecting the circuit to the battery and transformer, connect it to a variable power supply. Provide 12V DC and adjust VR1 till LED1  glows. After setting the high voltage  level, reduce the voltage to 10.5V and adjust  VR2  till  the  output  trips  off.  After  the  settings  are complete, remove the variable power sup-ply and connect a fully-charged battery to the terminals and see that LED1 is  on. After making all the adjustment connect the circuit to the battery and transformer. The battery used in the circuit is a 12V, 4.5Ah UPS battery.

Source :

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Wednesday, December 18, 2013

Build a Regulated Charge Pump Circuit Diagram

How to Build a Regulated Charge Pump Circuit Diagram. The dc-dc converter substitutes a voltage triplet in place of the external inductor and the diode that`s typically associated with the switching regulator, IC1. Inverting and non inverting amplifiers in the MOS-FET-driver (IC2) activate a diode-capacitor tripling network (D1 through D3, CI through C3). 

A 50-kHz oscillator residing within IC1 produces the EXT signal (pin 6), IC2 converts this signal into drive signals (180° out of phase) for the tripler. The resulting charge-discharge action in the capacitors recharges C3 toward 10 V every 20 The ferrite bead limits output ripple to about 20-mVpp for a 50-mA load. Conversion efficiency is about 70% for the 5-V input, 10-V output configuration.

Regulated Charge Pump Circuit Diagram

Regulated Charge Pump Circuit Diagram

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Simple 12 Volt 30 Amp PSU Circuit Diagram

Using a single 7812 IC voltage regulator and multiple outboard pass transistors, this power supply can deliver output load currents of up to 30 amps. The design is shown below:

Simple 12 Volt 30 Amp PSU Circuit Diagram

Simple 12 Volt 30 Amp PSU Circuit Diagram

The input transformer is likely to be the most expensive part of the entire project. As an alternative, a couple of 12 Volt car batteries could be used. The input voltage to the regulator must be at least several volts higher than the output voltage (12V) so that the regulator can maintain its output. If a transformer is used, then the rectifier diodes must be capable of passing a very high peak forward current, typically 100amps or more. The 7812 IC will only pass 1 amp or less of the output current, the remainder being supplied by the outboard pass transistors. As the circuit is designed to handle loads of up to 30 amps, then six TIP2955 are wired in parallel to meet this demand. 

The dissipation in each power transistor is one sixth of the total load, but adequate heat sinking is still required. Maximum load current will generate maximum dissipation, so a very large heat sink is required. In considering a heat sink, it may be a good idea to look for either a fan or water cooled heat sink. In the event that the power transistors should fail, then the regulator would have to supply full load current and would fail with catastrophic results. A 1 amp fuse in the regulators output prevents a safeguard. The 400mohm load is for test purposes only and should not be included in the final circuit. A simulated performance is shown below:

 Circuit Diagram

Simple 12 Volt 30 Amp PSU Circuit Diagram2

This circuit is a fine example of Kirchoffs current and voltage laws. To summarise, the sum of the currents entering a junction, must equal the current leaving the junction, and the voltages around a loop must equal zero. For example, in the diagram above, the input voltage is 24 volts. 4 volts is dropped across R7 and 20 volts across the regulator input, 24 -4 -20 =0. At the output :- the total load current is 30 amps, the regulator supplies 0.866 A and the 6 transistors 4.855 Amp each , 30 = 6 * 4.855 + 0.866. Each power transistor contributes around 4.86 A to the load. The base current is about 138 mA per transistor. A DC current gain of 35 at a collector current of 6 amp is required. 

This is well within the limits of the TIP2955. Resistors R1 to R6 are included for stability and prevent current swamping as the manufacturing tolerances of dc current gain will be different for each transistor. Resistor R7 is 100 ohms and develops 4 Volts with maximun load. Power dissipation is hence (4^2)/200 or about 160 mW. I recommend using a 0.5 Watt resistor for R7. The input current to the regulator is fed via the emitter resistor and base emitter junctions of the power transistors. Once again using Kirchoffs current laws, the 871 mA regulator input current is derived from the base chain and the 40.3 mA flowing through the 100 Ohm resistor. 871.18 = 40.3 + 830. 88. The current from the regulator itself cannot be greater than the input current. As can be seen the regulator only draws about 5 mA and should run cold.
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Tuesday, December 17, 2013

Protection For Telephone Line Circuit

A long time ago when telephones were so simple almost nothing could go amiss from an electrical point of view, Telecom operators installed surge protection on all telephone lines exposed to storm risks. Paradoxically, now that we are hooking up delicate and expensive equipment such as telephones filled with electronics, fax machines, (A)DSL modems, etc., this protection has disappeared.

However, if you have the good fortune to live in the countryside in a building served by overhead telephone lines, there’s an obvious risk of very high voltages being induced on the lines during thunderstorms. While we have lost count today of all of the modems, fax machines and other telephones that have been destroyed by a ‘bolt of lightning’, surprisingly you only have to invest a few pounds to get a remarkably efficient protection device like the one we are proposing here.

During a storm, often with lightning striking near a telephone line, the line carries transient voltages up to several thousands of volts. Contrary to the HV section of television sets or electrical fences, on which practically no current is running, in the case of lighting striking current surges of thousand of amps are not uncommon. To protect oneself from such destructive pulses, traditional components are not powerful or fast enough.

As you can see on our drawing, a (gas-filled) spark gap should be used. Such a component contains three electrodes, insulated from each other, in an airtight cylinder filled with rare gas. As long as the voltage present between the electrodes is below a certain threshold, the spark gap remains perfectly passive and presents an impedance of several hundreds of MW. On the other hand, when the voltage rises above this threshold, the gas is very rapidly ionized and the spark-gap suddenly becomes a full conductor to the point of being able to absorb colossal currents without being destroyed.

 Protection Circuit Diagram For Telephone Line :

The one we are using here, whose size is of the same magnitude as an ordinary one watt resistor, can absorb a standardized 5,000 amps pulse lasting 8/20 ms! Since we are utilizing a three-electrode spark gap, the voltage between the two wires of the line or between any wire and ground, cannot exceed the sparking voltage, which is about 250 volts here. Such protection could theoretically suffice but we preferred to add a second security device made with a VDR (GeMOV or SiOV depending on the manufacturer), which also limits the voltage between line wires to a maximum of 250 volts.

Even if this value seems high to you, we should remember that all of the authorized telephone equipment, carrying the CE mark must be able to withstand it without damage. This is not always the case however with some low-end devices made in China, but that’s an entirely different problem. Since pulses generated by lightning are very brief, the ground connection of our assembly must be as low-inductance as possible.

It must therefore be short, and composed of heavy-duty wire (1.5 mm2 c.s.a. is the minimum). If not, the coil, composed of the ground connection, blocks the high frequency signal that constitutes the pulse and reduces the assembly’s effectiveness to nothing. Finally, please note that this device obviously has no effect on the low frequency signals of telephones and fax machines and it does not disturb (A)DSL signals either.

Author: Christian Tavernier - Copyright: Elektor Electronics Magazine
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Build Motorcycle Alarm Circuit Diagram

This is a Motorcycle Alarm Circuit Diagram. Any number of normally open switches may be used. Fit the mercury switches so that they close when the steering is moved or when the bike is lifted off its side-stand or pushed forward off its center-stand. Use micro-switches to protect removable panels and the lids of panniers etc. While at least one switch remains closed, the siren will sound. 

 Motorcycle Alarm Circuit Diagram

Motorcycle Alarm Circuit Diagram

About tw1o minutes after the switches have been opened again, the alarm will reset. How long it takes to switch off depends on the characteristics of the actual components used. But, up to a point, you can adjust the time to suit your requirements by changing the value of C1.The circuit board and switches must be protected from the elements. Dampness or condensation will cause malfunction.Without its terminal blocks, the board is small. Ideally, you should try to find a siren with enough spare space inside to accommodate it. Fit a 1-amp in-line fuse close to the power source. 

This protects the wiring. Instead of using a key-switch you can use a hidden switch; or you could use the normally closed contacts of a small relay. Wire the relay coil so that it is energized while the ignition is on. Then every time you turn the ignition off, the alarm will set itself.When it`s not sounding, the circuit uses virtually no current. This should make it useful in other circumstances. For example, powered by dry batteries and with the relay and siren voltages to suit, it could be fitted inside a computer or any thing else that`s in danger of being picked up and carried away. The low standby current and automatic reset means that for this sort of application an external on/off switch may not be necessary.
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cell phone jammer will not intercept on the base station

 cell phone jammer will not intercept on the base station.
Visible, smart phones, large screen, large screen products favored by the users. Chinese mobile phone market in June 2011, the smart phone market with different screen sizes attention to the proportion of contrast. Case Study: Apples share of continued expansion. Apples global handset market share continued to expand. According to the U.S. market research firm Gartner statistics show that, since 2007, Apple introduced the iPhone smart phone, smart phone market, the pattern began to change. In 2008, Apple alone an iPhone, the global market share has reached 8.2 percent, while the first quarter of 2011, only three years, alone, four generations of iPhone products, Apples market share has reached 16.8%, to become the worlds first The three operating systems. cell phone jammer will just influence the downlink.
2007-2011Q1 Apple Worldwide sales of mobile phones and smart phone market share trend. Data sources Gartner, data management: ZDC. Apple user attention in the smart phone market in China is climbing. Rattling trend in the global mobile phone market with Apple, the Apple in the smartphone market, but also showed the fierce attacks, especially in cooperation with China Unicom, Apple users attention from record highs. The ZDC monitoring data show that the smart phone market in China in June 2011, Apple accounted for 9.2 percent of the concern proportion, only a difference of 2.6 percent and Motorola. In addition, from Apple released the data, the establishment of the ecosystem and no brand. This is a considerate design for cell phone jammer .
Since 2011, the three operators for 3G mobile terminals, a number of Central Purchasing universal low-priced products has always been an important source of new 3G subscribers, new subscribers expected to reach the end of universal terminal undoubtedly become the focus of the tender object, and an important platform to promote value-added services as operators necessary to support the role of popular intelligent terminal to enhance 3G users overall ARPU value are bound to become the top priority of purchases and sales. Sino Market monitoring data show that in October this year, 3G smart market 700 to 1500 the proportion of the price reached 54.7%, 24.6% increase compared to same period last year, up significantly. The insulation feature of cell phone jammer is very important for the customer.Products, the number of 3G thousands of intelligent machines models increase from 15 in October 2010 to October 2011, 123 models, thousands of intelligent machines has become a new force of the smart phone market. The low-end market into focus. IPhone users and thousands of intelligent machines the user using the data flow to compare, you can find iPhone users monthly data traffic is not significantly higher.
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Wednesday, June 12, 2013

ISL97672A power LED driver electronic project and circuits

Using the ISL97672A can be designed a power LED driver circuit that controls six channels of LED current for LCD backlight applications. The ISL97672A power LED driver is capable of driving LEDs from 4.5V to 26.5V, with a maximum output of 45V.
The ISL97672A power LED driver employs an adaptive boost switching architecture that allows Direct PWM dimming with linearity as low as 0.007% at 200Hz or 0.8% at 20kHz. Dimming can be as high as 30kHz.
This LED driver can compensate for non-uniformity of forward voltage drops in the LED strings. Its headroom control circuit monitors the highest LED forward voltage string for output regulation to minimize voltage headroom and power loss in a typical multi-string operation.
The IC features extensive protection functions that flag whenever a fault occurs. The protections include string-open and short-circuit detections, OVP, OTP, and an optional output short-circuit protection with a fault disconnect switch

LED drivers for direct, multiplexed videowalls, information displays circuits
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Will The Next Generation Iphone Be Called Iphone 4s

 According to a Web site message, the next generation iPhone may not be the iPhone 5, but may be named the iPhone 4S; If you really gone this route, it should be in terms of exterior design with the iPhone 3G to the iPhone 3GS, so nothing much has changed, while in the inner part, they will use the same series with the iPad 2 Apple A5 dual-core processor, but the photography is not whats heard of the Great Leap Forward features, the legendary eight megapixels, and will not appear with 1080p video, but still is five megapixels with 720p video, good news is that pre-video photography will be with the main camera module, like that time might have a 720p video.
    And although the appearance will look almost exactly the same, but the actual screen size, resolution is not clear; operating systems, WWDC will see the iOS 5 above preview, iOS 5 of the official launch date may not be too fast; OS shipped with the iPhone 4S still iOS 4.x, where the fork is still unclear, but the time will be published in September, when the time is listed along with black and white; As all this is true or not,  we just only wait for other official news!
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Wednesday, June 5, 2013

2005 Mitsubishi Lancer Wiring Diagram Electrical System

Wiring Diagrams  Cars on Get The Detail Car Stereo Wiring Harness Catalog Here     Free
Get The Detail Car Stereo Wiring Harness Catalog Here Free.

Wiring Diagrams  Cars on Keywords Starter Wiring Diagram Diagram Motorcycle Car Starter Circuit
Keywords Starter Wiring Diagram Diagram Motorcycle Car Starter Circuit.

Wiring Diagrams  Cars on Jeep Grand Cherokee Radio Adaptor Wiring Harness   Circuit Schematic
Jeep Grand Cherokee Radio Adaptor Wiring Harness Circuit Schematic.

Wiring Diagrams  Cars on Chevrolet Monte Carlo Wiring Diagram And Electrical Schematics  1997
Chevrolet Monte Carlo Wiring Diagram And Electrical Schematics 1997.

Wiring Diagrams  Cars on Ktm 250 525 Sx  Mxc  Exc Electrical System And Wiring Diagram
Ktm 250 525 Sx Mxc Exc Electrical System And Wiring Diagram.

Wiring Diagrams  Cars on 2005 Mitsubishi Lancer Evo Ix Wiring Diagram Electrical System
2005 Mitsubishi Lancer Evo Ix Wiring Diagram Electrical System.

Wiring Diagrams  Cars on Cassette   Cd And 6 Speakers Audio System Wiring   Circuit Schematic
Cassette Cd And 6 Speakers Audio System Wiring Circuit Schematic.

Wiring Diagrams  Cars on Peugeot 206 Wiring Diagram For Central Door Locking   Circuit
Peugeot 206 Wiring Diagram For Central Door Locking Circuit.

Wiring Diagrams  Cars on About Volvo 960 Electrical System And Wiring Diagram 1992 Here
About Volvo 960 Electrical System And Wiring Diagram 1992 Here.

Wiring Diagrams  Cars on Find More Information About 2002 Bajaj Legend Wiring Diagram Here
Find More Information About 2002 Bajaj Legend Wiring Diagram Here.

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Tuesday, June 4, 2013

Crossover Cable Source Destination Wires

Ethernet Cable Wiring on Limited   Ethernet Wiring Diagrams   Patch Cables   Crossover Cables
Limited Ethernet Wiring Diagrams Patch Cables Crossover Cables.

Ethernet Cable Wiring on Connectlink Wireless   Ethernet Wiring Diagram
Connectlink Wireless Ethernet Wiring Diagram.

Ethernet Cable Wiring on Ethernet 10   100 Mbit  Cat 5  Network Cable Wiring Pinout And Wiring
Ethernet 10 100 Mbit Cat 5 Network Cable Wiring Pinout And Wiring.

Ethernet Cable Wiring on Tech Info   Lan Wiring And Pinouts
Tech Info Lan Wiring And Pinouts.

Ethernet Cable Wiring on Ethernet Cable Connection Between The Dsl Modem And The Netgear Hub
Ethernet Cable Connection Between The Dsl Modem And The Netgear Hub.

Ethernet Cable Wiring on Cat7 Cables  100 Ohm Utp  Unshielded Twisted Pair  Ethernet Wiring
Cat7 Cables 100 Ohm Utp Unshielded Twisted Pair Ethernet Wiring.

Ethernet Cable Wiring on With A Crossover Cable  The Source And Destination Of The Utp Wires
With A Crossover Cable The Source And Destination Of The Utp Wires.

Ethernet Cable Wiring on Known As 568b  Is The Most Common Arrangement For Ethernet Cable
Known As 568b Is The Most Common Arrangement For Ethernet Cable.

Ethernet Cable Wiring on Cat 5 Ethernet Cable Standards Pin Out Assignments
Cat 5 Ethernet Cable Standards Pin Out Assignments.

Ethernet Cable Wiring on Ethernet Straight Through Cable Pin Configuration
Ethernet Straight Through Cable Pin Configuration.

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