220v to 200vac with triac

Hello, do you know if there is a way to get 200vac from grid using triac?
i want around 100mA
also is there any way to have isolation?

also, is there any easy way to increase the output voltage without smps and coils, to 300vac?

thank you

Would having a small amount of zero volts between half cycles be a problem? If not, you could get quite close with a couple of zener diodes and a couple of opposing rectifier diodes.



Isolation as well? Not that I know of without a transformer.

FoxyRick said:

Would having a small amount of zero volts between half cycles be a problem? If not, you could get quite close with a couple of zener diodes and a couple of opposing rectifier diodes.

View attachment 81320

Isolation as well? Not that I know of without a transformer.

Click to expand...

How does it differ from a rectifier the diodes turn on during a half cycle and the role of the zener is not clear sir

Can you pls clarify it here

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FoxyRick said:

Would having a small amount of zero volts between half cycles be a problem? If not, you could get quite close with a couple of zener diodes and a couple of opposing rectifier diodes.

View attachment 81320

Isolation as well? Not that I know of without a transformer.

Click to expand...

How does it differ from a rectifier the diodes turn on during a half cycle and the role of the zener is not clear sir

Can you pls clarify it here

Let's take one half of the circuit - a zener and its series rectifier. When the rectifier diode is forward biased and the zener is reverse biased by its zener voltage, it conducts. So, if we used a 20V zener and a rectifier diode with a 0.6V drop, then when the input rises above 20.6V in the correct polarity, the pair conduct but drop the 20.6V. So, the output potential is 20.6V less.

The other half (another zener with series rectifier) does just the same but on the opposite half of the cycle. So, we now have both halves of the cycle being conducted, but as if each half has been shifted towards zero, and the part between the turn-on of the diodes flattened. Not a perfect output (it's no longer a sine wave) but perhaps tolerable depending on what will be done with it.

Edit to add: Just to clarify the rectifier diodes' role: If they were not there, the zeners would conduct when forward biased like normal diodes, and we don't want because each half of the circuit would then prevent the other half from developing its 20V drop.

Note that in the diagram I have used 20V zeners.