Rear Fog Light Controller With Delay
We assume that most of our readers are thoughtful drivers who do not switch on their rear fog lights w...
Car Lights Monitor
This circuit is for the purpose of monitoring automotive lighting. Two special ICs are available from Telefunken that ar...
Auto Ignition Cut-Off
Using an SCR/relay combination, this circuit can be made to cut off ignition, unless a positive voltage is applied to...
Backup Beeper
When the vehicle"s backup lights kick on, or when the manual switch (SI) is closed, a small current is fed to the base of Ql....
Analog Expanded-Scale Meter For Autos
Zener diode D1 is used to suppress the first 6 V of the scale, which gives a meter reading of 6 to 8 ...
Automotive Electrical Tester
This little tester is useful for checking vehicle electrical circuits. Two LEDs indicate whether one of the cl...
Electric-vehicle-battery-saver
The battery life and operating cost of an electric vehicle is severely affected by overdischarge of the battery. This circuit provides both warning and shutdow...
Auto-battery-alternator-monitor
Most of the circuitry is contained in the LM3914 dot/bar-graph driver IC chip. In addition to the comparator circuitry within the package, it also contains a...
Headlight-alarm
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 head...
Flashing-third-brake-light
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 cyc...
Electronic-car-horn
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...
Back-up-beeper
Put the car in reverse and the circuit provides a loud, audible beep at the rate of about one per second (1Hz). Half of U1, a 556 dual oscillator/timer, is used...
Automatic-headlight-delay
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 conductio...
Directional-signals-monitor
A unijunction transistor audio oscillator drives a small speaker. The oscillator"s frequency is determined by resistor R2 and capacitor C2. The ope rating vo...
Automobile-voltage-regulator
A monolithic 555-type timer is the heart of this simple automobile voltage regulator. When the timer is off so that its output at pin 3 is low, the power Darli...
Automobile-air-conditioner
This circuit disables the air conditioner compressor when additional engine power is required. It does so by monitoring the engine vacuum at the intake manifol...
Delayed-extra-brake-light
Operating the brake pedal of the car brings on the normal brake lights and then, after a delay, the extra lights are turned on. ...
Lights-on-reminder
With both the ignition and the car lights on, piezo transducer BZl draws no current and remains silent. With only the ignition on, diode Dl is reverse-biased...
Courtesy-light-delay-switch
This circuit holds on the internal light for approximately one minute after the car doors are closed. When the door contacts open, a + VE pulse is applied to t...
Automobile-ignition
The ignition substitute provides a constant power source for the ignition coil. Its frequency, 0.5-1.0 kHz, is that used by an 8-cylinder engine with an idling...