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Showing posts with label make. Show all posts

Monday, April 1, 2013

Make This Powerful 200 200 watts Car Stereo Amplifier Circuit

No complex wiring, no costly MOSFETS and no cumbersome heatsinks, yet a powerful 200+200 watt amplifier circuit, which can be built within hours using just a couple ICs, right in your home.

Yes we are discussing the state-of-the-art thick film hybrid IC STK4050II, by SANYO.

The IC is specifically designed for amplifying music at an astounding rate of 200 watt power.

The involvement of minimal number of components especially makes this device perfectly suitable for the many hobbyists who aspire not only making a powerful amplifier at home but also for enjoying its application.

The IC is able to effectively drive sub-woofers and therefore also becomes ideally suitable as a car stereo amplifier.

See Pics and Specs HERE

The salient features of the IC STK4050II includes the following:

Compact streamlined package resulting a sleek looking amplifier design.

Simple heatsinking clamping facility with large surface area, for better heat dispersal, resulting in an enhanced output capability.

The internal circuitry of the IC entertains a constant current operation which helps reduce switch-ON and switch-OFF "thump" noise in the speaker.

Maximum Operating Parameters of the IC

Huge maximum power supply rating at +/- 95 volts resulting powerful outputs at lower currents.

Typical operating voltage may be around +/- 66 volts.

Speakers used at the output of the circuit should be ideally a 8 Ohm type.

Operating Characteristics are:

Quiescent current is internally set at 100mA for voltages upto Vcc +/-80 volts.

Output power with the above conditions will be around 200 watts.

Total harmonic distortion will not exceed 0.4% at frequencies between 20Hz and 20kHz.

Frequency response of the IC is also very high, between 20Hz and 50kHz.

The circuit diagram below shows a neat little amplifier circuit, two of them may be built for obtaining stereo outputs.

The configuration is very simple, mostly all the complexities are solely handled by the chip itself.

The input consists of a regular low pass filter components for rejecting high frequency interferences.

Other features like automatic gain control, offset control and stability control, everything is effectively tackled by the shown design.

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Tuesday, March 19, 2013

How to Make 1 A Constant Current LED Driver Circuit

The article explains a simple circuit using the IC MBI6651 from MACROBLOCK. The IC has been specifically designed for operating high power LEDs safely by providing a constant current output. The circuit includes very few external components and therefore becomes very easy to assemble at home.
About the IC MBI6651

The IC MBI6651 is a high efficiency, step down DC to DC converter chip capable of driving high power LEDs at a safe 1 Amp constant current.
The IC requires just four passive external components for making it functional.
The output current of the IC can be externally set by selecting the appropriate resistor value.
The IC also features a PWM controlled dimming control of the connected LEDs.
Some of the other outstanding features of this IC includes UVLO meaning under voltage lockout, over temperature shut down, LED open circuit protection and LED short circuit protection, all these ensure complete safety to the IC from wrongly configured output loads.

Typical Application of this device are:

Automotive decoration and illumination
LED flood lights using high intensity, high power LED.
The IC also can be used as a constant current source in particular circuit applications.

Setting the output Current

The output current of the IC is fixed through an external resistor Rsen. The output current Iout and the adjustment resistor Rsen has the following relation:
Given Vsen=0.1V
Rsen=(Vsen/Iout)=(0.1V/Iout)
Where Rsen is the value of the external resistor. This resistor is connected across the pin outs SEN and Vsen of the IC.
The optimum current with Rsen 0.1 Ohms is 1000 mA or 1 Amp.

Optimizing External Component Selection

Inductor: Two issues specify the inductor type, the switching frequency and the ripple current. The involved calculation can be written as:
L1>{Vin - Vout - Vsen - (Rds(on) * Iout)} * D/fsw * delta.IL
where, Rds(on) is the on-resistance of the ICs internal MOSFET. The value is typically around 0.45 at 12V
D is the duty cycle of the IC, given as D = Vout/Vin
fsw is the switching frequency of the IC

While designing the inductor for the given circuit, along with the inductance the saturation current must also be taken into account,because these are two basic factors which typically affects the overall performance of the circuit.
The rule of thumb, the saturation current of the inductor should be selected 1.5 times greater than the LED current.
Moreover, selecting high values for the inductance provides better line and load regulation.

Refer circuit diagram

Selecting the Schottky diode

The diode D1 shown in the circuit diagram basically acts as the flywheel diode for nullifying the inductor back emf during the periods when the LED is switched OFF.
The diode must be selected with the following couple of important characteristics:
It should have a low forward voltage rating and maximum possible reverse voltage tolerance.

Selecting the capacitor

The general rule is always to select a capacitor value with a voltage tolerance 1.5 times higher than the supply voltage.
Preferably, a tantalum capacitor should be selected because these have high capacitance and low ESR characteristics.

The proposed circuit of 1 Amp constant current LED driver circuit is given below:

The basic operating parameters are given below:

Pin Out Specs:

Courtesy: http://www.ledlabs.ru/pdf/macroblock/mbi6651.pdf

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Sunday, March 17, 2013

Make This Mains Transformerless LED Controller Circuit

Normally LED control circuits are based on buck boost or flyback principles, where the circuit is configured to produce a constant DC for illuminating an LED series.

The above LED control systems have their respective drawbacks and the positives in which the range of operating voltage and the number of LEDs at the output decide the efficiency of the circuit. Other factors like whether the LEDs are included in parallel or series or whether they need to bedimmed or not, also affects the above topologies. These considerations make these LED control circuits rather dicey and complicated.

The circuit explained here employs a different approach and relies on a resonant mode of application.

Though the circuit does not provide direct isolation from the input AC, it has the features of driving many LEDs with current levels as high as 750 mA. The soft switching process involved in the circuit ensures greater efficiency to the unit.

Basically the mains transformerless LED control circuit is designed around the fluorescent lamp dimmer control IC IRS2530D. The circuit diagram shows how the IC has been wired up and how its output has been modified for controlling LEDs in place of the usual fluorescent lamp.

The usual preheating stage required for a tube light utilized a resonant tank which is now effectively replaced by a LC circuit suitable for driving LEDs.

Because the current at the output is an AC, the need of a bridge rectifier at the output became imperative; this makes sure that current is continuously passing through the LEDs during every switching cycle of the frequency.

The AC current sensing is done by the resistor RCS, placed across the common and the bottom of the rectifier.

This provides an instant AC measurement of the amplitude of the rectified LED current.

The DIM pin of the IC receives the above AC measurement via the resistor RFB and capacitor CFB.

This allows the dimmer control loop of the IC to keep track of the LED current amplitude and regulates it by instantaneously varying the frequency of the half bridge switching circuit, such that the voltage across the LED maintains a correct RMS value.

The dimmer loop also helps to keep the LED current constant irrespective of the line voltage, load current and temperature changes.

Whether a single LED is connected or a group in series, the LED parameters is always maintained correctly by the IC.

Alternatively the configuration may also be used as a high current transformerless power supply circuit.

Courtesy - http://www.irf.com/pressroom/articles/594LEDP0902.pdf

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Saturday, March 16, 2013

Make a Simple Earth Leakage Circuit Breaker ELCB Circuit

An Earth leakage circuit breaker unit will silently monitor the electrical condition of your appliances and the Earth connection of your house. If anything goes wrong with them it will instantly switch off the mains and stop any further associated loss. A simple ELCB circuit is discussed here.

A simple circuit of an Earth leakage circuit breaker also called ground fault circuit interrupter is discussed in this article. The circuit once built and installed will silently monitor the “health” of the earth connection of your house and the connected appliance. The circuit will immediately switch off the mains on detecting a missing earth connection or a current leakage through the appliance body.

A leaking current through earth terminal is probably more dangerous than a short circuit in a domestic wiring. A short circuit hazard is visible and mostly tackled through a fuse or a circuit breaker unit. But earth current leakages may remain hidden for years, eating up your precious electricity and also weakening or deteriorating the wiring conditions and also the appliances. Moreover if the earth connection is not properly grounded due to improper conduction or breakage, the leakage may turn into a lethal shock over the body of the appliance.

Commercially available earth leakage circuit breaker units are very costly and bulky, involving complicated installation procedure. I have designed a simple circuit which is low in cost and yet handles the situation handsomely. The device will detect any current exceeding above 5mA through the earth passage and switch off the mains. The connected appliance will then need a diagnose or a total elimination. A leaking appliance not only wastes your electricity but also can be dangerous fatally.

Circuit Description

The proposed ground fault circuit interrupter or ELCB utilizes a simple principle of detecting the AC signal rather the applied or the leaking voltage. Here, the leaking AC may be too small to be detected as a potential difference using simple voltage detection configuration, therefore the leakage is effectively sensed as a frequency, using a simple audio amplifier stage.

As shown in the diagram, a simple bootstrapped amplifier network forms the main sensing stage of the unit.

Transistors T1 and T2 along with the associated passive components are wired up into a small two stage amplifier. The introduction of R3 becomes very crucial as it provides a positive feed back to the input making the circuit more stable and respond to minutest input signals.

The inductor L1 basically has two windings, the primary which is connected to the earth point of the socket has less number of turns, the secondary winding has six times more number of turns and is integrated to the input of the circuit via C1.

The role of L1 is to amplify any AC induced into its primary winding which can only happen in case of a leakage through the body of an appliance connected to the socket.

The above amplified leakage voltage is further amplified to a level enough to activate RL1, instantly disabling the input to the appliance and indicating the earth leakage fault.

Capacitor C5 along with D3 and C4 forms a standard transformerless power supply to power the circuit. D3 performs a dual function of rectification and surge suppression.

Interestingly the main earth connection itself becomes the negative of the circuit instead of the neutral line. Also since RL2 is directly connected to the supply across the positive of the circuit and the earthing, simply means that if the earthing becomes weak or disconnected, the relay will deactivate, cutting off the AC mains to the appliance, so it effectively indicates the health of the earthing and safeguards the house from faulty or missing earth connections.

ELCB Circuit Parts List.

R1 = 22K,

R2 = 4K7,

R3 = 100K,

R4 = 220E,

R5 = 1K,

R6 = 1M,

C1 = 0.22/50V,

C2 = 47UF/25V,

C4 = 1000UF/25V,

C6 = 2UF/400V PPC,

T1, T2 = BC 547B,

T3 = BC 557B,

Relays = 12V, 400 Ohm, SPDT,

All Diodes are = 1N4007,

L1 = Coil wound over a bobbin used normally with E-cores (smallest size,) begin winding 50 turns of 25 SWG wire first, tie it up and solder it to produce the primary terminals at one side of the bobbin. Now using 32 SWG copper wire, wind 300 turns over the primary winding, as before tie the ends to the other side of the bobbin by soldering. Insert and fix the coil within the E-cores. Secure it tightly using PVC tape

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Friday, March 8, 2013

Make this Thermo Touch Operated Switch Circuit Using IC 741

The circuit explained here employs a rather different approach for implementing a touch operated switch action. Here instead of the resistance, the warmth of the finger is used for sensing and operating the circuits output.

Irrespective of the ambient conditions, our hands and fingers mostly exhibits some extra warmth or increase in the level of the temperature compared to the atmospheric levels.

This feature of our body has been exploited here for making this thermally activated touch switch circuit.

The proposed thermo-touch operated switch circuit has its own distinct advantages in contrast to the normal "touch resistance" based switches.

This design is not prone to humid areas, or wet conditions where normally a resistance based switch would falter and generate erratic results.

The circuit utilizes the ubiquitous 1N4148 diodes whose forward voltage drop alters by about 2 mV in response to a rise of 1 degree Celsius temperature over it.

Looking at the circuit diagram, when the diodes D3 and D4 are touched with the finger, the voltage at point A drops rapidly in comparison to point B, sufficient to make the output of the IC 741 change state.

The IC 741 has been configured as a comparator, and it compares the forward voltage drop of the diodes with respect to the reference voltage clamped at point B.

The output generates a TTL or a CMOS compatible logic pulse at point C, which can be easily used for triggering a flip flop circuit and an intended load.

P1 and P2 are the presets which may used for setting and optimizing the circuits response or the sensitivity.

Parts List

R1, R4 = 10K

R2, R3 = 56K

R5 = 1K

R6 = 1M,

P1 = 10K preset,

P2 = 1K preset

C1 = 104/ disc

T1 = BC547

IC1 = 741

D1----D4 = 1N4148

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Wednesday, March 6, 2013

How to Make Any Light a Strobe Light Using Just Two Transistors

If you feel strobe lights very interesting but are disappointed by the fact that these wonderful light effects can be produced only through complex xenon tube then probably you are quite mistaken. It is very much possible to make any light a strobe light if you are equipped with a proper driving circuit capable of handling different lighting devices to generate the desired strobe light effect. The present article shows how a circuit as basic as a multivibrator may be modified in different ways and made compatible with ordinary bulbs, lasers, LEDs to produce spectacular light pulses.

A strobe light may be used for warning, scientific analysis or as an entertainment device, whatever may be the application the effects are simply dazzling. In fact it is possible to make any light a strobe light through a proper driving circuit. Explained with Circuit Schematics.

Introduction

A light when made to blink or flash indeed looks pretty eye-catching and that’s the reason why they are used in number of places as a warning device or for decorations. However a strobe light in particular may also be considered a flashing light yet is uniquely different from ordinary light flashers. Unlike them in a strobe light the ON/OFF pattern is so optimized that it produces sharp dazzling pulsed flashes of light. There’s no doubt why they are mostly used in conjunction with fast music to enhance a party mood. Nowadays green lasers are being popularly used as a strobing device in party halls and gatherings and have become hot favorite among the new generation. Whether it’s LEDs, lasers or an ordinary filament bulb, all can be made to flash or rather strobe using an electronic circuit capable of producing the required pulsed switching in the connected lighting element. Here we will see how we can make any light a strobe light using a simple electronic circuit.

The following section will acquaint you with the circuit details. Let’s go through it.

Pulsating any Light to Produce Strobing Effect

Through one of my previous articles we came across a nice little circuit able to produce interesting strobe effects over a few of the connected LEDs. But this circuit is only suitable for driving low power LEDs and thus cannot be applied to illuminate big areas and premises. The proposed circuit allows you to drive not only LEDs but also powerful lighting agents like incandescent bulbs, lasers, CFLs etc.

The first diagram shows the most basic form of a multivibrator circuit using transistors as the main active components. The connected LEDs can be made to strobe by suitably adjusting the two potentiometers VR1 and VR2.

The above circuit forms the base for all the following circuits through some suitable modifications and additions.

For example if you want to illuminate and pulsate a small torch bulb using it, you would just need to do the simple modifications as shown in the second diagram. Here by adding a PNP power transistor and triggering it through the collector of T2, a torch bulb is easily made to strobe. Off course, optimum effect is achieved only through proper adjustment of the two Pots.

As already discussed already in the previous section, green laser pointers are pretty popular nowadays; the diagram illustrated shows a simple method of converting the above circuit into a pulsating green laser pointer strobe light. Here, T3 and T4 form a typical current controlled transistor configuration – a must when vulnerable lasers are involved. The selection of R6 can be critical and will decide the current limiting threshold for a safe operating of the laser. A wrong calculation may instantly roast your costly laser bulb. The following formula may be used for calculating R6:

U = 0.6/Ilaser,

Where U = Operating voltage of the laser and the circuit.

I (laser) = Maximum safe operating current of the laser device.

The next diagram shows how an AC mains lamp may be used as a strobing light source using the above circuit. Here a triac forms the main switching component receiving the required gate pulses from T2’s collector.

Thus we see that through the above circuit designs it becomes very easy to make any light a strobe light simply by doing the relevant modifications.

Parts List

R1, R4, R5 = 680 Ohms,
R2, R3 = 10K
VR1, VR2 = 100K pot
T1, T2 = BC547,
T3, T4 = BC557
C1, C2 = 10uF/25V
Triac = BT136
LEDs = as per choice

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Saturday, March 2, 2013

How to Make a Cheap LED Name Plate with Illuminated Back Light

LEDs are no doubt gaining popularity by leaps and bounds and probably most of the illuminated decorative articles today incorporate LED as the light source. These devices are relatively cheap, extremely bright and outstandingly efficient with their operations.
Digital displays today also incorporate LED technology and we all know how impressive they look with the involved digits distinctly visible with an illuminated back light.
The back illumination especially gives a fuller look and helps to highlight the display in a better way.
However these displays can be pretty expensive and require microcontroller ICs for producing the involved illuminations. A new hobbyist may find it difficult to grasp and make such displays at home.
Using LEDs in series for designing alphanumerical displays consisting of the desired names and numbers looks good but these dont produce the effects which is generally obtained from a back illuminated displays.
A cheap way of making a back illuminated display or a name plate having the desired alphabets is explained here, lets see how we can implement the whole concept very cheaply.
For making the proposed back illuminated name plate circuit design we will basically require the following very few of the components.

Four high bright LEDs, color will depend on the user preference, I used blue LEDs in my prototype because my party wanted blue back light illumination for his displays.
A rectangular plastic lens, made up of acrylic material.
PCB as shown in the figure.
Positive film of the desired name or, a screen printed film with the name portion kept transparent while the rest of the area painted black and opaque.
150 Ohm resistor, 1 no.

Refer circuit diagram

How to Make the Display.

Connect the LEDs and the resistor as shown in the figure below such that the LEDs focus the light across the length of the rectangular PCB.
Cut the acrylic lens such that it perfectly fits in between the LEDs, make notches or grooves at the lens ends for making a snug fitting with the LEDs.
Now scratch one of the surfaces of the acrylic lens with a polish paper or an emery paper, such that it becomes rough and grainy on that surface and almost opaque for a clear vision, this operation is the secret behind producing a perfect and uniform back light.
Place a white paper cut to size on the PCB such that the light from the LEDs floods the white paper across the length.
Next place the lens in the center of the LED, over the PCB and the above white paper with its roughened surface on the top side.
Next place the positive film of the name display over the above lens.
Switch ON power to the LEDs, wow! your name plate is glowing bright with an illuminated back-light thats uniformly lit across the whole displayed name.
Put insulation tape over the side ends of the unit such that light does not escape from these areas.
Enclose the whole unit inside a suitable rectangular box for displaying it in the preferred location.

PCB, LED and the Lens Set Up