Electronics > Beginners
LAB POWER SUPPLY
glinjik:
Hi I'm getting the idea of creating a variable lab power supply but instead of using potentiometers I'm thinking of using a variety of fixed volt regulators with a multi position switch to switch the volt regs and thus change the output is this a viable idea or just pie in the sky?
rstofer:
Sure, this will work well and is a very reasonable approach. +-15V +12V +9V(?) 5V and 3,3V should about cover it. The only negative voltage you are likely to need is -15V for op amps and that dual voltage supply could be entirely separate. I might skip the 9V.
Using regulators like the 78xx for the positive voltages and the 79xx for negative voltages should work well.
The alternative is variable regulators (that could be configured for a fixed voltage) like the LM317 for positive voltages or LM337 for negative voltages would have all the regulators identical with the output adjusted with resistors (or a trim pot).
rdl:
There's at least one commercial product that does this, but the voltages are selected in 1.5 volt increments to match batteries, so not as useful as it could be.
You could use a single LM317 and switch between various resistors electronically or with a mechanical switch.
edit: Found one
https://www.amazon.com/Philmore-Multi-Voltage-Regulated-Power-Supply/dp/B004M45MHQ
glinjik:
hmmm food fo thought I've a lot of different volt regs here like ЕН8б that's en8b in English 12volt fixed reg got lots of different ones here. i suppose the amperage heeds to be the same or at least not exceed the volt reg with the lowest amperage i have 4 identical 220/19v transformers each pushing about 1/2 amp could be used in series parallel course i need a descent schematic a friend donated I think it's a 20 pole mechanical switch Russian military origin thats, what's given me the idea the last power supply is adequate but im not entirely happy has no real oomphh i can charge a car battery but over a looong period the over current protection works well maybe im a born fiddler :-/O but thank you for replies i think a bit of planning is needed
glinjik:
came across this sort of idea
--- Quote from: rdl on January 13, 2020, 06:49:31 pm ---There's at least one commercial product that does this, but the voltages are selected in 1.5 volt increments to match batteries, so not as useful as it could be.
You could use a single LM317 and switch between various resistors electronically or with a mechanical switch.
edit: Found one
https://www.amazon.com/Philmore-Multi-Voltage-Regulated-Power-Supply/dp/B004M45MHQ
--- End quote ---
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