Bench power supply dilemma

I can pick up a couple of new single output power supplies for about $50 each. they retail for about $200. Would I be better off with a dual output supply, even though I'd probably pay more for a used unit? They are Protek 303's.

Two single supplies is fine - IF their outputs are isolated from their Chassis/MainsGround.

Most lab PSU's are.

The point is, that you need the PSU to be isolated from Chassis/MainsGround in order to be able to "stack" them to build a symmetric supply voltage, as needed for e.g. opamp projects..

Jakob E.

I have narrowed down a few choices, but I'm still undecided. The two single output supplies are brand new in the box, and cheap.

I found a Topward dual tracking supply used that looks interesting.

Also a Lambda with digital readout. Doesn't look like it's a tracking type.

What are the pros and cons of digital readout? My Bob Pease book recommends analog.

Hi.

If the two PSUs are cheaper I would buy them. On the picture there are the connectors + - and GND so I will bed the Eartch is isolated.
To get a symmetrical output voltage simply put two cables into the first power supply (+ and -) (this is your pos. voltage, connect a cable from the first PSU + ot the second psu + and the - will be the negative voltage output.

I like digital displays because the read errors are at the minimum. (I don't know what paralaxe fehler means in english) :?
An analog meter could be better to read if the currect changes very fast.

Frank.