All,
I am looking to buy my first benchtop power supply. I have already done the ATX power supply and decided it was somewhat useful but not what I would like.

I have been looking at one of the Mastech triple output supplies (Linear $199, switching $239). 30V, 5A. http://www.mastechpowersupply.com/d...triple-outputs-30-v-5a-new-model/prod_81.html

As I mostly do microcontroller with sensing circuits, I am assuming this is more than enough V & A. These prices are really pushing the budget but I do not see myself buying another PSU.

This is a HOBBY, not a career!

Questions:
Anyone own Mastech and what is your opinon of it?

Additionally, Anyone in the USA makes a similar product?

Thank you, Bob

 

Hi Bob,

I've looked at those too. They appear to have a decent value equation. But, like you, I was not able to find much in the way of reviews or experienced users. IF they actually meet their specs, it would be a nice supply for what you are planning to use it for, I would just caution regarding the lack of fixed voltage options on some of those models. It would be too easy to turn it up for some test, then hook up your favorite upc and smell smoke! (NOT that I've ever done that...) I also was not too sure about fine adjustment controls on them, as I recall. (Yeah, recall from a guy that can't remember to turn down his voltage on his variable supply! Ironic isn't it?)

Would you post the model numbers you're looking at so we can be sure of the specs? And if you do run across reviews, let me know where?

Thanks,
-fab

 

@ fab

The photo shows model number HY3005D-3

It might be the machine in question.

 

Here's something to think about. Even if you only do it as a hobby, it's possible that it will be a hobby you do for a long time. I like to follow the maxim "Buy the best and cry only once". The things I use the most besides my DMM are my DC power supplies. My favorite is my HP 3615A, which I found in new condition on ebay for $100 delivered -- a steal. If a hobbyist is willing to wait and look for good deals, you'll eventually find something similar. Of course, most of us aren't willing to wait.

My other favorite power supply is my B&K 9130. I was able to get this new at a discount in a trade for some work; otherwise, I probably wouldn't have been willing to cough up the $900 to buy it. However, it's really three independent supplies in one and is a very handy power supply to have on the bench. It replaces a Heathkit tracking DC power supply I built in the 1970's. I like that I can put the supplies in parallel or series to get other outputs. For example, I can put the two 30 V channels in parallel to get 6 A output or in series to get 60 V 3 A output. And then they're controlled with just one control. Or I can put all three channels in parallel to get 6 V out at 9 A (great for burning up logic circuitry ).

Note both of these supplies give you the ability to set a maximum output voltage. Thus, if you're e.g. working on a circuit that you don't want to be powered by more than 5 volts, you can set the maximum output to 5 volts and never worry that the supply will output more than this, no matter what you type in or how you turn the knobs. Older supplies like the HP use a crowbar circuit for this protection, but newer ones like the B&K just do it in firmware.

Oh, by the way, these supplies can operate in both constant current and constant voltage mode. I use constant current mode a lot, perhaps more than I do the constant voltage mode. I recommend getting a CV/CC supply if you purchase one. For example, one use is it lets you easily and safely measure current-voltage relationships of components -- rather than setting the voltage and reading the current, you set the current and measure the voltage. As long as you know the maximum rating of the device you're measuring, it's harder to damage the device this way.

 

...

As I mostly do microcontroller with sensing circuits, I am assuming this is more than enough V & A. These prices are really pushing the budget but I do not see myself buying another PSU.

This is a HOBBY, not a career!
...

Why not build one? It's so easy with 2 LM317 regulators on a heatsink, you can have adjustable current limiting and adjustable voltage regulation. 30v up to about 1.5A is typical and should be plenty for small hobby stuff.

You can also buy cheap panel meters either digital or analogue and make quite a nice bench supply.

You might also find for "hobby use" you end up needing more than one supply, so a couple of 1.5A bench supplies like these will be more useful than one good brand name bench supply.