Wiring Schematic diagram

The CDI ignition circuit produces a spark from an ignition coil by discharging a capacitor across the first of the coil.
A 2uF capacitor is charged to regarding 340 volts and also the discharge is controlled by an SCR. A Schmitt trigger oscillator (74C14) and MOSFET (IRF510) are used to drive the low voltage aspect of alittle (120/12 volt) power transformer and a voltage doubler arrangement is employed on the high voltage aspect to extend the capacitor voltage to regarding 340 volts.
an analogous Schmitt trigger oscillator is employed to trigger the SCR regarding four times per second. the ability provide is gated off throughout the discharge time so the SCR can stop conducting and come back to it’s blocking state. The diode connected from the 3904 to pin nine of the 74C14 causes the ability provide oscillator to prevent throughout discharge time.
The circuit attracts solely regarding two hundred milliamps from a twelve volt supply and delivers virtually twice the conventional energy of a standard ignition circuit. High voltage from the coil is regarding 10KV employing a 3/8 in. spark gap at traditional air temperature and pressure.
Spark rate may be increased to probably ten Hertz while not losing abundant spark intensity, however is restricted by the low frequency power transformer and duty cycle of the oscillator. For faster spark rates, the next frequency and lower impedance provide would be needed.
Note that the ignition coil isn’t grounded and presents a shock hazard on all of it’s terminals. Use CAUTION when operating the circuit. An alternate methodology of connecting the coil is to ground the (-) terminal and relocate the capacitor between the cathode of the rectifier diode and also the positive coil terminal. The SCR is then placed between ground and also the +340 volt aspect of the capacitor. This reduces the shock hazard and is that the usual configuration in automotive applications.