Capacitor replacement rule and selection method

1. The replacement rule of capacitor

(1) When the capacity and withstand voltage are the same and the volume is not limited, the ceramic capacitor and the paper capacitor can be replaced with each other;

(2) When the price is the same and the volume is not limited, the mica capacitors with the same withstand voltage and the same capacity can be used instead of the metallized paper capacitors;

(3) When the working frequency and insulation resistance value are not high, the metallized paper capacitor with the same withstand voltage and the same capacity can replace the mica capacitor;

(4) If unconditionally limited, a capacitor with the same capacity withstand voltage can replace a capacitor with low withstand voltage, and a capacitor with small error can replace a capacitor with large error;

(5) Regardless of the frequency influence, the same capacity, metallized paper capacitor with the same withstand voltage can replace the glass glaze capacitor;

(6) When the moisture-proof performance is not high, a non-sealed capacitor of the same capacity and withstand voltage can replace the sealed capacitor.

(7) Two or more large capacitors with different capacities and different withstand voltages can be used instead of small capacitors; the withstand voltage of capacitors after series should be considered that the voltage drop across each capacitor should be within the allowable range of withstand voltage;

(8) Parallel two or more different withstand voltages, small capacity capacitors without capacity can replace large capacitors, and the withstand voltage after parallel connection is based on the withstand voltage of the minimum withstand voltage capacitor.

2. Capacitor selection method

(1) For capacitors that are not required to be high, paper capacitors or ceramic capacitors are generally available;

(2) High-frequency ceramic capacitors, mica capacitors or through-core ceramic capacitors should be used in high-frequency circuits;

(3) In the higher frequency intermediate frequency and low frequency circuits, a film capacitor can be selected;

(4) In the power supply filtering, decoupling circuit, aluminum electrolytic capacitors are generally available;

(5) For circuits with high reliability requirements, paint film capacitors, mica capacitors and tantalum electrolytic capacitors should be used;

(6) In the tuning circuit, inverter capacitors and trimmer capacitors should be selected;

(7) For high voltage circuits, variable capacitors and micro-investigation capacitors should be used.