Automobile-ignition


Posted on Feb 6, 2013

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 speed of 650 RPM, and the unit provides a rapid spark at a 17% duty cycle, while staying within the power dissipation limits of the components. The circuit consists of a 555 timer IC configured as an astable free~running multivibrator that is used to drive a high-current npn transistor, such as a 2N6384. The transistor should be heavily heatsinked because it might be drawing several amps over quite a long period of time.


Automobile-ignition
Click here to download the full size of the above Circuit.

The coil ballast can be from 0.68 to 6.5 0, depending on what"s available. The 2.5-0, 20-W ballast shown works well. All the other resistors can be either 1/4-or 1/2-W devices, and the capacitor, between pins 1 and 5 of the 555, can range from 0.01 to 0.051"F. Do not omit the 100-V, 0.05-I"F capacitor across the transistor; it prevents voltage spikes from damaging the device. Although designed for an 8-cylinder engine, this device can be used with other types. In addition, a neon bulb can be added to the circuit to verify the presence of a spark.




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

38KHz or 40KHz signal generator
Audio Amplifier Volume Indicator
LM1875 20 Watt Audio Power Amplifier
plant watering watcher dry soil detector
1W guitar amplifier
Open source USB scope
Electronic Torricelli Barometer



Top