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Hi Sven,
When turning off the thyristor with current through the coil a flyback voltage is made. The flyback pulse (kick back) has to go somewhere as else it destroys something. If making a switching converter transistors are preferable as switches. Of course it is possible to use the slow thyristors. This was done before power transistors got the size to do that job. For higher power and low frequency the thyristor may still be a choice.
Some old TV-sets used thyristors for different purposes. That was in the overlap of tube and transistor ages. I haven't really seen how that works but just heard that it was hell to fault seek. Thyristors are better for AC current as this makes them turn off at zero current and turn on anywhere on the half cycle.
For a passive circuit the current would have to pass a capacitor which cuts off the current when fully charged.
Regards
Ole
---In [email protected], <s.friedrich@...> wrote :
Hello Ole, I expressed myself a little unhappily with a heartbeat, I meant a full cycle. 1/4 cycle to load and the next 1/4 cycle to unload. I've built an extra circuit with a scr to test the LC circuit. Unfortunately on the anode side with the load and cathode directly on minus pol. The problem is that there is no resistance at the cathode which limits the current so that the capacitor can even charge. I had thought just to put a capacitor in parallel between the cathode and winding so that the stored current charges the capacitor and turns off the thyristor, perhaps the thyristor shuts off sooner. The circuit should be passive but if you have an idea!?! Greetings Sven
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