> Yes, where the load is on the emitter. You could also use one of > those FETs. I"d rather see the zener to common with a resistor > above it drawing some reasonable current to give a less able to > oscillate voltage to the base or gate...
Zener to input gives you a fixed drop, so the transistor doesn't have to handle a wide range of conditions. I suppose you could use a JFET as a constant current source instead of the resistor. If you used a FET instead of a BJT the zener/resistor would be isolated from the load, add a bypass cap on the gate, should take care of oscillations. But keep in mind, this is driving a second regulator, so minor ripple won't be as bad. They do make high voltage zeners, though, if you want to do it the "normal" way. _______________________________________________ geda-user mailing list [email protected] http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
