Masteck linear supply, take two.

I have a couple of different model Mastecks, and they work fine into a short. 3003D and 3003D-3, the triple.

FWIW, the high power switching ones won't go anywhere near zero either. We had to put some big 300W resistors in series with coils.

Just tried that with mine, Mastech HY6003D, current into a dead short. Works fine, nicely adjustable.

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Thanks All,

Grumble, It figures we'd pick the one that has 'issues'. I pulled a new one off the shelf and it was the same. Maybe I should write to Mastech. It seems if they can make the 60 Volt version work they should be able to do it at 50.

George H.

I have the schematic for the 3005 if you need it. Not exactly the model you've got but should be similar. Mastech would also likely send you the one for yours if you ask nicely.

I like the cute little Lascar supplies, but they only go down to 1.2 volts.

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Thanks Joerg, but don't bother. The last thing I want to do is try and fix someone else=92s mistake. I should maybe buy a lower voltage version 3003. But for the moment we'll just recommend an Agilent.

George H.

I second that Agilent recommendation. I don't want to give the impression that I work for Agilent, because I am often talking about how many of their gadgets I buy and love (and also about the ones that I have had trouble with)

But,

Until the U800xA series came out, Agilent bench supplies were much more $$$ for comparable performance, and frankly too expensive and also a goofy UI. I basically hate the E3631A that was their older precision programmable, low power 3x offering.

Now there are several digitally programmable supplies by the "big names" for less than $400 which I consider a very good price for quality:

1. Agilent U800xA series 2-394

I keep 1-2 of those laying around for loaners.

1. Tektronix PWS2185, PWS2323, PWS2721, PWS2326

Agilent also added a triple version:

1. Agilent U8031A, U8032A k

If you want precision there's this nice new thing from Tek:

1. Tektronix PWS4205, PWS4305, PWS4323, PWS4602, PWS4721

I recently bought a copy of the Tek PWS2xxx and PWS4xxx series to check out. Unfortuntely, they don't have very great transient response/settling time specs of 400us vs. 50-100us for the Agilents, but I'm not sure if it will really matter or be as bad as that for all conditions. I'll hopefully get to fiddle with them in the next few weeks.

1. Sorensen XDL series

I have bought a Sorensen (used to be Xantrex) XDL 35-5 for home, despite the $766 because I liked it so much based on the 2 I have at work. Having both keypad entry AND knob (with choice of decimal place to increment) on the XDL makes for a very convenient UI. Plus a V*I readout button!

In general the Sorensen line has a great variety of very interesting supplies.

I'm considering this B&K 9130 triple to put on my publicly shared workbench in my work lab as well:

I'm a fan of the old Power Designs blue ones.

Cheers

Phil Hobbs

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Thanks Mr CRC. I saw those Teks. No knob.

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I saw those Sorensen's too. They looked nice. Like the Kenwoods we were using. But twice as much.

Thanks again for the advice.

For lots of things I'd be happy with a 12V 1A supply, that should be cheap.

George H.

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Yeah sure, It's CV when the voltage is set too low.

George H.

All linear supplies i have used require that the O.C. voltage be set above the required loaded value to work in constant current mode.

The current limiter transistor tends to blow up on them.

The Hoeffer Scientific PS500XT 0-500V, 0-0.4A switching supply gets to zero "constant" current if the voltage (like i mentioned earlier about linear supplies) is set above the required value for the load presented. Note the quotes. The _AVERAGE_ current is as advertised on the front panel digital meter. BUT. To do that, it switches on at some higher value then off and back again, repeating in a saw-tooth manner. That cannot be fixed short of a complete re-design. Oh, yes, another redeeming quality is that in constant voltage mode, there are these "dinky" switching spikes in excess of 1.5V peak to peak. Common mode chokes do not help at all; any addition of "reasonable" series chokes or parallel caps to the output terminals can cause havoc in supply" operation. Natch, those in Biology Labs do not care..

Try the baby bird (goo gull), you may be pleasantly surprised.

Hmm, never had that problem in 20 years or so of use.

Cheers

Phil Hobbs

The MPJA Item Number: 9615 PS is similar to the Lascar. It's rated 0-3A, 0-30V. I just checked it on the bench - it goes down to 0 volts. I mentioned in another thread that I replaced the 1 turn pots with 10 turn pots, which took some careful drilling. Well worth the effort, and the supply is well worth the $49.95 price. It might work for George if he doesn't need > 30V.

Ed

Very small electroplating rectifier? Lionel train transformer at a low setting? Both will likely have a lot of ripple.

The bench low voltage high amp supplies that HP sold have some correspondence to modern Agilent lines. e.g. Agilent U8002A.

Tim.

Who is Baby Bird?