So, I assembled this useful device for my amateur radio laboratory – a zener diode tester. In order not to mess with transformers, I applied a step-up step-up module on the MC34063, which I used to do. Here is his schematic and PCB :

And installed my voltmeter:

50 volt voltmeter, 40 volt converter. The scheme turned out like this:

Perhaps something needs to be changed, adjusted, but it works like that.

We insert tweezers into the terminals and go ahead to sort the zener diodes.

Zener diodes, if you need to test for 100 V or 300 V, then you should assemble such a circuit:

And accordingly, take a voltmeter for more voltage.