I'm not too familiar with "current transfomers" I bought one a few years ago to experiment with, but haven't been able to find the time to do that yet.
What I understand is that you need to provide a current path on the secondary side or otherwise the voltage on the current transformer will become very high.
As the primary function of the current transformer is to transform the current, it will adapt the voltage to make that happen. If the diode is conducting: no problem. 0.6V extra on the secondary side. maybe about 0.6mV extra on the primary side.
But when the diode blocks. no current can flow on the secondary side. So the voltage goes up until the diode starts conducting regardless of its efforts to try to block.... Not good. Provide an extra diode for that path. It would be pointing upwards and would be connected directly across the pins of the current transformer. Moving the zener to the other side of the diode would probably also work. You'd restrict the range by 0.6V, so if you can find a slightly larger-value zener, that'd be nice.
Actually though I don't think the 0V6 reflects back into the primary, the current is what matters and that is not affected by the diode voltage
In reverse bias? As you say not good. Does the diode go open or short? If short the Zener is forward biased If open then what? This is apparently a commercial product. Did you look at the frequency range of the CT?
I hope I did not mark my own comment as "the correct answer" I did not mean to do so. And I don't seem to be able to mark any more a helpful - that's not helpful.
I hope I did not mark my own comment as "the correct answer" I did not mean to do so. And I don't seem to be able to mark any more a helpful - that's not helpful.
