Five major considerations for replacing the capacitor

The failure phenomenon of fixed capacitance is leakage, short circuit, circuit breakage and bad contact between internal leads of capacitor. In particular, the failure rate of electrolytic capacitors is much higher than that of other types of capacitors. Frequent failures of electrolytic capacitors include leakage, capacity reduction, breakdown and electrolyte leakage. When the capacitance is damaged, the original model shall be used. But there are many kinds of capacitors, such as the same type.The following notes are as follows:

1.The nominal nominal value of the substitute can float on the base of the nominal value of the original capacitor, and the range of the floating capacity is larger for the power filter capacitor and the bypass capacitor, but the capacitance of some circuits must be nominal value when the capacitor is replaced. Otherwise, the work of the circuit will be abnormal. For example, the capacitance of resonant circuit and time constant circuit must be replaced by the original nominal value. Another example is the coupling capacitance between the TV receiver and the cathode of the picture tube. The capacitor must be replaced by the original nominal value after damage, otherwise the quality of the image will be affected.

2. The rated voltage of the substituted capacitor must be greater than or equal to the rated voltage of the original capacitor or greater than the actual working voltage of the actual circuit.

3.The frequency characteristic of the substitute capacitor must satisfy the frequency requirement of the actual circuit, or replace the capacitor with low frequency characteristic with the capacitor with high frequency characteristic.

4.Mica capacitor and ceramic capacitor can replace paper capacitor. Ceramic capacitors can replace mica capacitors and glaze capacitors. The tantalum electrolytic capacitor can replace the aluminum electrolytic capacitor.

5.When there is no suitable capacitor replacement, capacitors can be used in series and parallel to obtain the appropriate capacitance. If the voltage of the capacitor is not enough, a series connection can also be used to increase the withstand voltage. For example, the capacitance of the circuit is 25V, and the capacitance is 500uf. Only the capacitance of 1000uf/16V can connect two 1000uf/16V capacitors in series. After series connection, an equivalent capacitance of 32V and capacitance of 500uf can be obtained.