Help Please! I need help understanding this circuit

Thread Starter


Joined Sep 2, 2019
Please I need assistance in understanding this circuit. I read about this circuit in a paper, its meant to limit current in the diode connected to the inductor. The paper gave a vague circuit without giving any information on sizes of electronic element. In order to understand its behavior I decide to simulate the circuit with arbitrary values. It seems to be working but I dont understand how. An explanation of the circuit would be much appreciated.
The Op amp has a Max and Min Output of 15 and -15 v and a gain of 1K.

Thanks in advance for the help



Joined Jul 11, 2016
your current test :: the 1H in series with ~ 100fF to 300pF diode-capacitor make a positive resonant feedback that takes a long startup stimulus and eventually destroys your op amp pos. input transistor or the entire op amp . . .

it seems the ideal opamp can run it relatively fast Falstad live! (?takes a double GO! however)

? do you have the paper or link to the source schematic
Last edited:


Joined Sep 17, 2013
Welcome to AAC!
Where is the power supply?
With two diodes back-to-back I don't see how the circuit does anything useful unless it is relying on diode reverse-breakdown.