Tee Hee! Made a voltage regulator today.

I find it hard to believe the use of 2 enhanced mode Mosfets, 2 R's and

Of course, you need to contend with the Vgs(th) voltage in the math for the knee point of the zener and all the other stuff, also, I wonder how stable the error fet Vgs(th) is with variations of temperature, which wouldn't be a good thing to have your set point wandering around with temperature changes.

Jamie

snip

Are you sure you don't have a (some) dried out electrolytic capacitor(s) in that supply?

If the voltage is not all that critical then maybe a simple capacitance multiplier would do just fine.

regards, tm

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no-one claimed it was

Yea, getting that much anti-molybdenum for the plates and anti-barium oxide for the cathodes woulda been tough. Not to mention setting up the factory...

the

I thought it was quite relevant -- NT obviously thought I might have been gilding the lily, and mentioned a simpler alternative.

It happens that I wasn't (or at least I don't think so), but I thought it was a perfectly valid point.

Tim's Vreg approach is more suitable this time. For most apps with a hum issue, RCRC is all that's needed.

NT

What, you don't thing that an LM78135 shouldn't be used in all cases like this?

(Gotta check Digikey to see how easy those are to get...)

Why do you limit the zener current so much?

Ed

Hmm I would have to think about that question a bit, I suppose the behavior or a zener would imply that I should obey the rules of meeting the knee currents how ever, I find that it actually works in this case, at least a variant of that above I used a couple of times in a photo multiplier.

Btw, that circuit has only been used in 60hz applications, I suppose it would be better to bring the zener closer to its knees in most cases.

Jamie