Zener diode problems

Guest · Post by **Guest** » Thu Jul 31, 2008 3:29 am

Hi, I have managed to get PowerSwitch working on one of my older pcs, but only if i do not use zener diodes in the circuit. However, it does not work on my new pc with or without zeners. I read somewhere on these forums that 1W zener is too high and I should use lower wattage, could this be the cause of my problem from these symptoms?

Post by **christian** » Thu Jul 31, 2008 12:26 pm

Yes. Zener diodes have a high capacity which distorts the signals. Low power diodes have less capacity. And the nominal voltage is measured at lower currents for low power types. You may have to choose a higher voltage for higher power types.

For an experimental circuit, you may try several Si-diodes in series to limit the voltage to ca. 3.0 to 3.3 V in idle mode, best measured at D-.

Guest · Post by **Guest** » Fri Aug 01, 2008 1:18 am

Thanks for the reply, It works fine now with 500mA diodes.