Testing method for fixed capacitors

1. Detection of small capacitors below 10pF: Due to the small capacity of fixed capacitors below 10pF, using a multimeter for measurement can only qualitatively check for leakage, internal short circuits, or breakdown phenomena. When measuring, a multimeter with R × 10k range can be used, and two probes can be connected to either pin of the capacitor. The resistance value should be infinite. If the resistance value (pointer swinging to the right) is zero, it indicates that the capacitor is damaged by leakage or internal breakdown.
2. Testing fixed capacitors with 10PF~001 μ F: By determining whether there is charging phenomenon, the quality can be judged. The multimeter is set to R × 1k gear. The beta values of both transistors are above 100, and the penetration current should be small. 3DG6 and other models of silicon triodes can be used to form composite transistors. The red and black probes of the multimeter are respectively connected to the emitter e and collector c of the composite tube. Due to the amplification effect of the composite transistor, the charging and discharging process of the measured capacitor is amplified, which increases the amplitude of the multimeter pointer and facilitates observation.
It should be noted that during testing operations, especially when measuring capacitors with smaller capacities, the pins of the tested capacitor should be repeatedly switched to contact points A and B in order to clearly see the swing of the multimeter pointer. For fixed capacitors above 001 μ F, the R × 10k range of a multimeter can be used to directly test whether the capacitor has a charging process and whether there is an internal short circuit or leakage. The capacitance of the capacitor can be estimated based on the amplitude of the pointer swinging to the right.