Rick,
I think I understand, in this simulation the coil never saturates it simply stops charging at 8AMPs. The very sharp upward part of the trace (after the knee) is simply the voltage across the transistor's 'ce' junction as it starts to turn off and limit current.
Quote:
Originally Posted by rick-l
The ideal inductor in the simulation will never saturate.
From 0 to 3.4 mSec the current ~ linearly rises to 8 amps. The voltage rise over that period is due to the sense resistor and the resistance of the drive transistor.
When the current gets near 8 amps the amplifier in the DME reduces the drive to the base of the Darlington and Vce rises, the slope based on the gain of the differential pair amplifier.
The plateau is the voltage required to maintain di/dt = 0 (Vind = 0) across the copper loss in the coil.
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