Capacitor Discharge Unit Circuit Diagram

This type of ignition builds up a charge quickly.

Capacitor discharge unit circuit diagram.

The input to the cdi unit is derived from two sources of the alternator. It then shows how to c. The led will light to indicate when the unit is ready. The modern cdi is an electronic version of the contact breaker which uses sophisticated electronic parts for generating the required arching across the spark plug.

A capacitor discharge ignition works by passing an electrical current over a capacitor. Referring to the above capacitor discharge ignition circuit diagram we see a simple configuration consisting of a few diodes resistors a scr and a single high voltage capacitor. Should a solenoid be left in circuit by the switch being held for a long period the current flowing through the coil after the initial surge will be less than 0 05a so it will not damage to the coil. Too high a voltage can also be a problem as the point motor may move the point over with so much force the point tiebar is shaken to bits.

Capacitor discharge unit cdu1c cdu2c cdu4c. A cdi ignition starts by generating a charge and storing it up before sending it out to the spark plug in order to ignite the engine. See the completed wiring diagram for the connections to the capacitor discharge unit. A capacitive discharge ignition unit also called the cdi unit is the modern alternative for the age old contact breakers which were quite crude with their functions and reliability.

However 12 volts dc provides too little power to move the points reliably. Capacitor discharge ignition cdi or thyristor ignition is a type of automotive electronic ignition system which is widely used in outboard motors motorcycles lawn mowers chainsaws small engines turbine powered aircraft and some cars it was originally developed to overcome the long charging times associated with high inductance coils used in inductive discharge ignition idi systems. When a point is operated the led wilt extinguish then come back on as the capacitor charges. The capacitor discharge unit can also be powered with dc.

A capacitor is a device that stores electrical energy in an electric field it is a passive electronic component with two terminals. This video shows how to connect a capacitor discharge unit up to a power supply and a set of points using a switch to set the points. The led can be placed on the main control panel of the layout to indicate the condition of the unit.