Re: 250mA voltage clamp




I need to limit the output of an ordinary unregulated power supply. The voltage ranges from 18V to 35V, taking load and line variation and ripple into account, and the load draws up to 250mA. 


	What's wrong with a 24 volt zener?  Pick one that will handle
the dissipation when the supply is current limited by its internal
impedance.  What is the current from the supply when it has a load
heavy enough to drop its output voltage to 24 volts?

The interesting question is how he plans to limit the I/O differential to 2V with 35V in and 24V out- looks like 12V to me, and at 1/4 amp makes for 3W. Sounds like someone is confused, again.

.

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