1. Capacitors are generally represented by "C" plus numbers in the circuit (for example, C13 represents the capacitor numbered 13). A capacitor is a component composed of two metal films that are close together and separated by insulating materials. The characteristics of capacitors are mainly to block DC and AC. The size of the capacitor capacity is the size of the electric energy that can be stored. The blocking effect of the capacitor on the AC signal is called capacitive reactance, which is related to the frequency and capacitance of the AC signal.
Capacitive reactance XC=1/2πfc (f represents the frequency of the AC signal, C represents the capacitance)
The types of capacitors commonly used in telephones include electrolytic capacitors, ceramic capacitors, chip capacitors, monolithic capacitors, tantalum capacitors and polyester capacitors.
2. Identification method: The identification method of capacitance is basically the same as that of resistance, and it is divided into three types: direct marking method, color marking method and number marking method. The basic unit of capacitance is expressed in farads (F), and other units are: millifarads (mF), microfarads (uF), nanofarads (nF), and picofarads (pF).