Common Components Identification - The Capacitor

- Jan 09, 2018 -

Common components identification - The Capacitor

The capacitor

1, the capacitance in the circuit generally with "C" plus numbers (such as C223, said number 223 of the capacitor). Capacitor is composed of two pieces of metal film close to the middle with insulating material composed of components. The characteristics of the capacitor is mainly isolated DC AC.


Capacitors on the circuit board

The size of the capacitor capacity is the size of the electrical 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.

Capacitance resistance XC = 1 / 2πf c (f represents the frequency of the AC signal, C represents the capacitance capacity)

Phone types commonly used in the capacitor electrolytic capacitors, ceramic capacitors, chip capacitors, monolithic capacitors, tantalum capacitors and polyester capacitors.

2, Identification method: capacitance identification method and resistance identification method is basically the same, points straight standard method, color standard method and the number of standard method 3 kinds. The basic unit of capacitance is Faraday (F). Other units include: mF, uF, nF and pF.

Including: 1 Farad = 103 milliampere = 106 microfarads = 109 Nafa = 1012 picofarad capacitance of the capacitance value directly on the capacitor, such as 10 uF / 16V capacity of the capacitor capacity value in the capacitor with letters Expressions or numbers indicate.

Letter representation: 1m = 1000 uF 1P2 = 1.2PF 1n = 1000PF

Digital representation: the general three-digit capacity, the first two significant figures, the third figure is the rate.

For example: 102 means 10 × 102PF = 1000PF 224 means 22 × 104PF = 0.22 uF

3, Capacitance tolerance table


Such as: a ceramic capacitor capacity of 104J said 0. 1 uF, the error is ± 5%.


104 ceramic capacitors

4, Fault characteristics

In the actual maintenance, the capacitor failure mainly as follows:

(1) Lead corrosion caused by broken open circuit fault.

(2) Desoldering and Weld open circuit failure.

(3) leakage caused by small capacity or open circuit failure.

(4) leakage, serious leakage and breakdown breakdown.