Automotive Circuits
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When the driver depresses pushbutton switch S1, timing capacitor C1 charges to 12 V and turns on transistor Q1, which drives power transistor Q2 into conduction. This, in tum, energizes the relay which has its contacts connected in parallel with the....
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An LM556 dual oscillator/timer, U1, configured as a two-tone oscillator drives U2, a dual4-watt amplifier. One of the oscillators, pins 1 to 6, contained in U1 produces the upper frequency signal of about 200 Hz, while the second oscillator, pins 8 to 13,....
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The circuit keeps the courtesy light on for 30 seconds after you close the door. The lead from the door switch is removed and connected to the 555 circuit. The 555 is arranged in a monostable mode, and is triggered by the door switches. The output drives....
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When power is first applied, three things happen: light -driving transistor Ql is switched on due to a iow output from U2 pin 3; timer U1 begins its timing cycle, with the output, pin 3, becoming high, inhibiting U2"s trigger, pin 2, via D2; and charge....
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The base of Ql is connected to the car"s ignition circuit. One side of the piezoelectric buzzer is connected to the instrument-panellight fuse. When the headlights are off,. no current reaches the buzzer, and therefore nothing happens. What happens when....
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This gauge uses a sensor in conjunction with R1 to develop a dc voltage proportional to oil pressure. IC1 and IC..
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This little tester is useful for checking vehicle electrical circuits. Two LEDs indicate whether one of the cl..
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A bridge circuit is used to produce a signal from the output of vacuum sensor IC1. IC2b provides about a 0.2 V offset ..
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This circuit uses a digital voltmeter (formed from IC1 and IC3) to display fuel quantity as a percentage of a full tank...
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Using an intersil ICL 7106 A/D converter chip and an LED display module, this gauge uses a Sensym Corp. pressure tra..
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This circuit uses an RCA CA3162E (IC2) A/D converter. This converter has 12-bit output (BCD) which is sent to display decoder..
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The circuit automatically turns on when the car is turned off. It gives you a variable time to get out and lock..
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SI is external key switch. The alarm allows a 0- to 45-s delay after SI is operated before the circuit is armed. During this per..
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Using an SCR/relay combination, this circuit can be made to cut off ignition, unless a positive voltage is applied to..
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In this circuit, IC1A and IC1B act as a monostable multivibrator. Any input from the sensors SI through..
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With a single IC, you can build a simple, reliable auto burglar alarm or a similar alarm. See (a) for the timing informatio..
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This circuit is for the purpose of monitoring automotive lighting. Two special ICs are available from Telefunken that ar..
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We assume that most of our readers are thoughtful drivers who do not switch on their rear fog lights w..
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The circuit is designed to light (via SCR1 and SCR2) only when both the left and right brake lights are activated. The ci..
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Because power for the circuit is obtained from the car"s side lights, the circuit can"t oscillate unless the lights are o..
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It is annoying to realize that you have left your car headlights on only to find that the battery is flat. One possib..
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This circuit turns on the brake lights of a parked car when the headlights of an oncoming car are detected, wa..
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The circuit can be used to give a visible or an audible warning that the headlights are on. It uses a 2N1305 ..
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In the wiper-delay schematic shown, with the ignition on, Dl maintains regulated +12 Vdc. When SI closes..
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This electronic ignition circuit is intended to be inserted into a car"s conventional ignition system. In effect, it re..
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NOTE: FOR BRIDGE CONFIGURATION: t install jumpers ju2 and ju4 2.remove j 1)3 3.remove rio 4replace ..
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The windshield wiper interval circuit presented here is very compact and is noteworthy for its use of ..
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At the heart of the CD4-MX is an astable multivibrator, built around Q1 and Q2, that feeds step-up transformer Tl. The output of 1 is rectified by D3 to D6 and used to charge capacitor C4. When the points close, a small voltage is fed to the gate of SCR1,....
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STS schematic. The Q2 gate voltage increases with the charge on C3. After 15 seconds of charging, the buzzer will warble. As the charging continues, the sound will grow louder.Circuit waveforms. Point A shows the signal from the flasher. The voltage at....
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When power is first applied, three things happen: the light-driving transistor (Ql) is switched on because of a low output from U2, pin 3; timer Ul begins its timing cycle, with the output (pin 3) going high, inhibiting U2`s trigger (pin 2) via D2; and....
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Only one channel of this circuit is shown. The other is practically a carbon copy.The input to the circuit, taken from your car radio`s speaker output, is divided along two paths; in one path, a high-power divider network (consisting of R8 through R10)....
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The headlight flasher is nothing more than a 555 oscillator/timer that`s configured as an astable multivibrator (oscillator). Its input is used to drive the gate of an IRF53IND hexFET, which, in turn, acts like an on/off switch, ..