[0-30V Stabilized Power Supply]

I'm in New Zealand and none of my usual component suppliers have those op-amps. Like I say, I can get them via mail-order but not in time for me to start building this weekend! I'll play around with the circuit as-is and see what happens while waiting for the op-amps to come from overseas.

Cheers

Dave.

[0-30V Stabilized Power Supply]

Thanks again. I notice that earlier this year a guy named Ivan has added some suggestions to the bottom of the original circuit description page. He recommends adding a 7809 regulator and a zener to limit the voltage to the op-amps and connecting the relevant power pins and a couple of other circuit points to that new bus to reduce overhead voltage. In theory it sounds fine, though he also says to join 2 3055's with emitter resistors (which I have seen done in many other circuits) for current handling, because the single one got too hot. I don't recall anyone else mentioning this though.

The only reason I am stuck on using TL081s is because I cannot source any of those other op-amps from any of the suppliers I deal with. I might bread-board one up over the weekend using the 7809 idea and see how that performs; I'm not after something whizz-bang, so this might be good enough for what I want to do.

Thanks for your guidance and expertise.

Dave.

[0-30V Stabilized Power Supply]

Hi Dave,
The latest version uses a choice of two common and inexpensive opamps. Their max allowed supply voltage is 44V and they work with their inputs as low as the negative supply voltage. Their outputs go down to the negative supply voltage:
MC34071 opamp by Motorola, ON Semi or Freescale Semi.
TLE2141 opamp by Texas Instruments.

The opamps should be available almost anywhere (but not at Radioshack and maybe not in the country of Bangladesh).

Thanks for the prompt and efficient replies Holt and Audioguru. If I understand your post correctly AG, the original circuit is fine as long as the hardier op-amps (and transistor) are used. Or, are you referring to the latest version as being the modified circuit referred to by Holt with those chips instead or the frail ones? I might just be building this over Easter I think....

PS. Apparently I live in a first-world country but nobody supplies these chips locally (and we have some very good components stores). I can get them by mail-order but otherwise they are not easily obtainable. Guess I'll have to go in another direction. Thanks anyway.

[0-30V Stabilized Power Supply]

If you use the TL081 then you should use a low voltage transformer then the max output voltage from the project will be about 22V, not 30V.
Many of the parts will still get too hot.

We modified it so that the max output is 30V and it is reliable.

Hi there. I have followed this project for some time and while I think it is one of the better power supply circuits around (hence 35 pages of forum discussion on it), I am still confused as to what the actual outcome of all this discussion has been. I built one based on the circuit on the original site and of course it blew the guts out of the op-amps and I threw the rest away in disgust. Months later I found this forum and have read as much as I can of it without my eyes watering. There appear to have been several mods to the original circuit to lower the voltage to the op-amps, therefore saving their lives, and the authors claim the supply works OK, but then there are other rewrites of the circuit to use different op-amps, many of which can't be found locally, so I am at a loss which one to go for. On top of that, so many parts lists and circuits are bandied about here I don't know which goes with what and what version is the one to build. Can someone please summarise for me what the upshot of everything is and, if I was to build one tomorrow, which circuit and parts list would I be best to use. Thanks and sorry for being so lame.

Dave.