On 6/11/2015 2:08 AM, wrote:
On Thursday, June 11, 2015 at 12:00:30 AM UTC-4, Trevor Wilson
wrote:
I'm looking for a cheap and cheerful bench power supply. Here are
the desired specs:

50-0-50 Volts, variable. 0-3 Amps, variable. Tracking

Ideally, I would like:

0-5 Amps Linear rather than SMPS 230/240VAC

The last three are not deal-breakers though. I've seen a few on
eBay, but am not certain about quality. Like this:

http://www.ebay.com.au/itm/Dr-Meter-...em338dca 9adf



It would be nice to find one here in Australia, but 30-0-30 seems to be
the limit for the popular choices.

-- Trevor Wilson www.rageaudio.com.au

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I would want my bench power supply to be as quiet as possible. Who
cares about efficiency when you're designing and powering up a
prototype. You may wind up with a switcher in the final design but I
would definitely not get a switcher frr new product evaluation.
Lenny.


Switchers plus cap multipliers are pretty good. If you're willing to
spend a volt or two of headroom, you can get ~100 dB rejection at SMPS
frequencies.

You can put a shunt regulator on the cap multiplier to get better load
regulation, e.g. by making it run exactly 2 volts below the input
supply. (You obviously have to filter the thing you're tracking, as well.

While it doesn't work at your power level, one of my favourite
approaches is to use some random laptop power brick followed by 150-kHz
Simple Switchers with toroidal inductors and cap multipliers. Easy,
cheapish, very quiet, no messing around with mains voltages.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net