The rule of thumb is that when a diode is fully on, it looks like a short circuit (ideally). So (to make this easy), say I have 100 V source and a diode which breaks down at 10V. If my power supply/source impedance is 1 Ohm, will the current through my diode be:

  1. I = (Vsupply - Vdiode)/Rsupply = (100 - 10)/1 = 90/1 = 90 Amps, or
  2. I = Vsupply/Rsupply = 100/1 = 100 Amps?
  • \$\begingroup\$ What is the question? \$\endgroup\$ – AndrejaKo Feb 3 '11 at 17:04

The current will be the same for all parts of the circuit, and in this case be about 90A as the diode can be considered to be a low resistance 10V drop.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.