I have a circuit specifying a 1000V 6Amp diode . I have several 50 volt 6 amp diodes. Can I use them in parallel to reduce 120 volt AC to 12volt DC via a resistor? thanks, Mike <SNIP>

 

in my opinion no you cant , because your diodes handel 50 volt and you want to connect it to 120 v , it would explosion because the angle of the the capacity is too big .

 

You probably mean - can you connect diodes in series to increase the overall voltage rating. You can do this provided you make additional circuit provisions to compensate for the different reverse leakage properties of individual diodes in the series string.

In any case this sounds like a proposal for a transformer-less rectifier /power supply circuit which is a taboo topic on the forum.

 

You probably mean - can you connect diodes in series to increase the overall voltage rating. You can do this provided you make additional circuit provisions to compensate for the different reverse leakage properties of individual diodes in the series string.

@fortunare . before you ask, the easiest way to compensate for different reverse leakage currents is to provide a higher then leakage current path in parallel to each diode, i.e. to put a resistor in parallel with each diode , all resistors having the same value.

example: peak value of 120ac is 169V, if you put 4 or better 5 diodes in series you could put 47k in parallel with each diode. (common low wattage resistors.)

The best value however depends on the diodes characteristics/model.

Can I use them in parallel to reduce 120 volt AC to 12volt DC via a resistor?

This looks like a strange to do, sure that's what you want?

 

If you have a circuit that really needs a 1000V diode, then in principle you might be able to substitute it with at least 20 (!) identical 50V diodes in series, each with a parallel bleed resistor to equalise the voltages across them. The result would be a rather leaky composite diode with a big forward voltage drop; whether or not that would work would depend on the application.

Reducing 120V AC to 12V DC with diodes and a resistor seems a different proposition. For this, I would not expect to need a 1000V diode in the first place, but as someone else has mentioned transformer-less mains power supplies are not discussed here.

Could you please describe your requirement in more detail?