How does the Capacitor Wizard® ignore other in-circuit parts?
There are four EXTERNAL parallel parts that could interfere with in-circuit ESR measurements: inductors, resistors, solid state junctions, capacitors. Parallel inductance: The test frequency is high enough ( 100khz ) to force expected inductive reactance (power transformers, coils) many orders of magnitude higher than the ESR scale. Parallel Resistors: Resistors found around capacitors 1uf and up will be large values compared to the Capacitor Wizard®’s low input impedance (2.5ohm). Parallel resistors have little effect on the reading and can be ignored. Solid State Junctions: The test voltage is less than 20 mv pp, too low to turn on any GOOD solid state devices. (You can use the Capacitor Wizard® to find leaky or shorted diodes, transistors IN-CIRCUIT!) Parallel Capacitors: Rarely will you encounter a circuit design using parallel capacitors. One leg of a parallel cap must be lifted. Both caps can then be individually tested.
