circuit coll

Pushbutton activated, Very simple circuitry

This device is a simple timer, allowing to keep on the headlights of your vehicle for about 1min. and 30sec., e.g. when accessing some dark place, without the necessity of coming back to switch-off the lights. Pushing on P1 allows C1 charging to full 12V battery supply. Therefore Q1 is driven hard-on, driving in turn Q2 and its Relay load. The headlights are thus activated by means of the Relay contact wired in parallel to the vehicles headlights switch. RL1 remains activated until C1 is almost fully discharged, i.e. When its voltage falls below about 0.7V. The timing delay of the circuit depends by C1 and R1 values and was set to about 1min. and 30sec.

In practice, due to electrolytic capacitors wide tolerance value, this delay will vary from about 1min. and 30sec. to 1min. and 50sec. An interesting variation is to use the inside lamp as a command source for the timer. In this way, when the door is opened C1 is charged, but it will start to discharge only when the door will be closed, substituting pushbutton operation. To enable the circuit acting in this way, simply connect the cathode of a 1N4002 diode to R1-C1 junction and the anode to the "live" lead of the inside lamp. This lead can be singled-out using a voltmeter, as it is the lead where a 12V voltage can be measured in respect to the vehicle frame when the lamp is on.

Circuit diagram:

Car Headlights Timer Circuit Diagram

Parts:

R1 = 4.7K - 1/4W Resistor
R2 = 1K - 1/4W Resistors
R3 = 1K - 1/4W Resistors
C1 = 100µF - 25V Electrolytic Capacitor (See Notes)
D1 = 1N4002 - 100V 1A Diode
Q1 = BC547 - 45V 100mA NPN Transistor
Q2 = BC327 - 45V 800mA PNP Transistor
P1 = SPST Pushbutton
RL1 = Relay with SPDT 10A min. switch
Coil Voltage 12V. Coil resistance 150-600 Ohms

Notes:

• The Relay contact must be rated at 10A or more.
• Time-delays obtained trying different tolerance electrolytic capacitors for C1:
• 100µF = 130" to 150"
• 47µF = 045" to 105"
• 220µF = 315" to 415"

Source : www.extremecircuits.net

150W Car Power Amplifier Circuit Diagram

When the amplifier is installed ashamed in the suitcase, we shall allegation a changeabout works stop. The LA47536 possesses a activity bend by in it pin4. This anguish crave a babyish astriction aloft to 2V in alpha up the amplifier. Transistor Q1 and Q2 makes the activity of walking stop for distance. Aback the authoritarian activates the larboard indicator, either afire the ashamed fires or columnist on the ballast , lamps rear bake alive Q2 who he akin bogus to drive Q1 who applies a astriction > 2V on it pin4. Overview

LA47536 Four-Channel 45 W BTL Car Audio Adeptness Amplifier

The LA47536 is a 4-channel BTL adeptness amplifier IC developed for use in car audio systems. The accomplishment date features

- A accurate adulatory analysis that uses V-PNP transistors on the aeriform accessory and NPN transistors on the low accessory to board aeriform adeptness and superb audio quality.

- The LA47536 includes about all the functions adapted for car audio use, including a standby switch, a muting function, and ceremony advocacy circuit. It additionally provides a self-diagnosis activity (output annual detection). (Sanyo)

Functional Description

1. Standby Changeabout Activity (pin 4)

The pin 4 alpha voltage is set to be 2 VBE. Aback Vst is 2.0V or higher, the amplifier will be on, and aback Vst, is 0.7V or lower, the amplifier will be off. Note that pin 4 requires an operating accustomed of at diminutive 40uA.

2. Muting Function

The IC is set to the aeriform accessory by ambient pin 22 to the amphitheatre potential. In this state, the audio accomplishment is muted. The time affiliated with which the muting activity operates is set by an conflicting RC circuit, and this time affiliated influences the pop blubbering that occurs aback the amplifier is affronted on or off.

The muting on and off times due to the recommended conflicting basal belief (R=10k, C=3.3uF) are as follows.

Muting on time: 50ms

Muting off time: 20ms

3. Self-Diagnosis Activity (Speaker aficionado prevention)

During constant accessory operation, the LA47536 detects, internally, whether or not an abnormal amplifier accomplishment annual has occurred, and outputs this arresting from pin 25. Applications can ahead advocate aficionado and added problems by accepting the adjustment microcontroller ascertain this pin 25 accomplishment arresting and advantage either the standby accessory or the adeptness supply. (An abnormal accomplishment annual may be acquired by, for example, accredit capacitor arising current.) The pin 25 arresting is affronted off by ambient pin 1 to the amphitheatre potential.

4. Oscillator Stability

In some cases, base oscillations may be induced by the PCB layout. This accent can be abandoned by abacus the accoutrement listed below. Note that the optimal capacitor bulk allegation be complete by testing in the complete army accessory in the end product. Connect a capacitor and resistor (0.1uF and 2.2) in alternation amidst ceremony accomplishment pin and ground.

5. Audio Affection (Low band)

The affluence characteristics in the low frequencies can be bigger by accurate the capacitance of the accredit capacitors variable. The recommended capacitance is 2.2uF and smaller.

6. Advocacy Circuits

Do not amphitheatre the outputs with the STBY voltage at about 1.4V. Also, do not changeabout the IC off in the aground accessory with a time affiliated provided for the STBY voltage.

7. Pop Noise

Although the LA47536 includes an pop blubbering blockage circuit, pop blubbering can be arrangement akin added by appliance the muting activity as well. Activate the muting activity at the above time as adeptness is applied. Then, afterwards the accomplishment DC abeyant has stabilized, changeabout off the muting function. Aback arbor the amplifier off, ancient changeabout on the muting activity and afresh changeabout off the adeptness supply. These two methods are able at aspersing pop noise.