Detection of variable capacitor

1. Gently rotating shafts with hands should feel smooth and should not feel sometimes loose tight or even stuck.

When driving axis forward rear upper lower left and right direction the shaft should not loosen phenomenon.

2. Rotating shafts with one hand and touching the outer edges of the group lightly shall not feel any loosening phenomenon.

Variable capacitors with bad contact between rotating shafts and moving pieces cannot be used anymore.

3. Put multimeter into 3 × 10 K block, one hand connected two tables separately to variable capacitor's dynamic plate and plate tip end, another hand rotating shaft several times.

The multimeter pointer should be fixed at infinity.

If pointer sometimes points to zero during rotating shaft there exists short circuit point between moving plate and plate;

If encountered certain angle multimeter reading is not infinite but appears certain resistance indicating that there exists a leakage phenomenon between variable capacitor dynamic plate and fixed chip.