Capacitors are electrical components that can store electrical energy within a certain period. It is said in a certain period because even though the capacitor is filled with an electric charge, the charge will run out after a while, depending on the capacity of the capacitor. The capacity of the capacitor is measured in Farad units. In practice this size is too large, so smaller units such as microfarads (µF), nanofarads or picofarads are used.
Capacitors have two types, namely:
Polar capacitors In polar capacitors, there is a determination of the poles of the capacitor if it is to be connected to a circuit, and only works on DC voltage. Polar capacitors have a relatively large capacity
Non-polar capacitors Non-polar capacitors do not have poles so they can be installed in an upside down position on the circuit and can be connected to AC voltage. The size of most non-polar capacitors is relatively small, with nanofarad and picofarad units.
The capacitor has the maximum working voltage indicated on the label on the housing. The voltage of the electrical circuit connected to the capacitor must not exceed the maximum working voltage of the capacitor concerned, because it will cause permanent damage (even in some cases, an explosion occurs). This maximum working voltage ranges from: 10V, 25V, 35V, 50V, 100V for polar capacitors and 250V to 750V for non-polar capacitors.
There are 2 practical provisions regarding capacitors, namely: 1) Capacitors that are empty of charge act as if the conductor (conductor), and 2) Capacitors which are full of charge act as if the insulator (insulator).
Example of a Capacitor Application on a Motorcycle
Application / use of capacitors in motorcycle electrical systems can be found in a series of conventional ignition systems (using platinum), and ignition CDI (Capacitor Discharge Ignition) both CDI with DC current (direct) and CDI with AC current (alternating).
The capacitor in the CDI unit works to store a temporary current (100 to 400 V) from the magnet that has been directed first by the diode when the SCR (Silicone Control Rectifier) is not active. After the gate G on the SCR is given a signal current for the ignition process, the SCR will be active and deliver an electric current from the anode (A) to the cathode (K). With the functioning of the SCR, causing capacitors to release current (discharge) quickly. Then the current flows into the primary coil (primary coil) of the ignition coil to produce a voltage of 100 to 400 volts as the induced voltage itself.
As a result of self-induction of the primary coil, then induction occurs in the secondary coil with a voltage of 15 KV to 20 KV. The high voltage then flows into the spark plug in the form of a spark that will be used to burn a mixture of fuel and air in the combustion chamber.