Is it OK to use 1N4007 diodes in series to drop VDC?

[doug08]

I have 12v, and need 9v. I have a bunch of these diodes laying around. I connected several in series and the voltage is now 9v. The diodes are rated for 1A. Doing this will only lower the voltage and have no effect on current? I do not want to lose available current, just lose some voltage.

Thanks.

 

[manish12]

it will obviously lower the current ,

 

[doug08]

OK.....How about (3) 9.1v 1W zener diodes in parallel after a resistor? I need a 250ma supply....each zener is only rated for 100ma. Using (3) in parallel would give 300ma max?

 

[IanP]

If you say you need "only" 300mA you can use 1N4007 diodes without much trouble ..
These diodes are rated for 1A and they will deliver it ..

Each diode will drop roughly 1V@1A and that's all ..

No worries, mate, you can use them ..

IanP

 

[keith1200rs]

it will obviously lower the current ,

No it will not! As Ian has said, series diodes will work. It is not precise, but will work. A shunt regulator using a zener and correctly sized power resistor will also work and produce a more stable voltage. A linear regulator would be even better.

Keith

Added after 2 minutes:

By the way, don't parallel up underpowered zeners or diodes - they will not equally share the total current.

Keith

 

[FvM]

The question can't be answered without knowing the expectable current variation and required voltage accuracy. But you should be
able to answer the question yourself. Consider, how the diode voltage drop will change with load current and temperature (get the
values from a datasheet or do your own measurements) and determine, if it fills your needs.