We have all had difficulty testing diodes in-circuit. Most DMM’s have a diode Vf function that measures forward drop, but what is the normal voltage drop?

This circuit can also be used to check forward voltage drop across diodes and LEDs at a pre-setted value of current. Here the maximum test current is near 12 mA with the 2.7K ballast resistor (R3) ...

When checking and verifying capacitors, inductors, diodes, bipolar transistors, and cables, the gamut of test methods can range from those used to confirm a defective component to identifying the ...

However, the circuit described here performs a simple go/no-go test on these diodes while limiting forward current and reverse voltage to safe levels (see the figure).

The circuit is simple enough: it uses a capacitor, a resistor, and a pair of diodes (one of them a zener diode). He uses this basic circuit to drive simple regulators with input and output filter ...