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Does a hobbyist need a bench power supply?

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So, all these projects we are making all require power, so an essential piece of equipment is something to power all of these.

My first power supply was an Irwin variac power supply, which provided AC and smoothed, unregulated DC. I got it from a skip at school as the plastic casing was smashed and the banana plug sockets damaged. I then found it also had a 110V winding which meant you could get twice as much output voltage. It served me well until my dad chucked it out in a clear up whilst at uni.

Since then I have relied on wall-warts (for most digital/microprocessor based work), custom built (e.g. +/- supplies for amplifiers), and a single-ended programmable switch mode bench supply (a GWInstek PSP-2010 which I got because it was £100 in clearance at Rapid, and is very useful for battery charging, testing motors and so on).

I'm feeling the need to get a proper bench power supply now - but I'm not quite sure why. Maybe it's because I see them on everyone else's bench. Maybe I'm just annoyed at having to build a 1.2/3.3/5/12/15V power supply each time I need one.

So what to people feel they need in a bench power supply? Is dual output with independent/parallel/series enough? Do we even really need a variable power supply for most projects? How much current is enough?

I've been looking at these two: - which is mentioned here: (GSP-4303 - I've bought from these guys before, their prices are very good).

Any thoughts? Any bargains knocking around?

In my opinion, yes. It's used to power something before the power supply is finished, and to independently test the modules. Or just for experiments.

I use the variable current limit to set the current limit just barely above the normal current draw, so nothing blows up when shorted. The variable voltage is useful to test things like minimum voltage (eg. dropout voltage of a regulator). There have been various topics on this forum about them. You can also build one yourself, they're not that complex.

Tracking is useful for op-amps which need symmetrical power supplies. Amount of current depends on your projects, I rarely use more than a few hundred milliamps, but I also know people that have and use 10A+ power supplies.

I would say that a variable voltage power supply is one of the things you need after a multimeter but don't bother buying one, build your own. My bench power supply is based on a LM317 variable voltage regulator, will supply current up to 1.5 amps but it only has a 1 amp current meter and best of all the voltage is variable from 1.2 volts to 13 volts which is pretty much all you need for doing hobby electronics. If you need current limiting, which is handy, you can use a L200 voltage regulator which will go up to 2 amps but the voltage will only go down to 2.85 volts. My next power supply project will prolly include + and - fixed regulators of various voltages for op amp work as well as the variable supply. The internet is awash with schematics and data sheets so you can easily find a design to suit your needs.

i'd say fairly essential, primarily for the reasons before, variable and current limiting.

less useful is the atx to bench conversion, since its neither of those

For me a bench power supply is essential. I don't need variable current, but variable voltage is a must have.

I don't think it would be a good idea for a beginner to build one himself. Mains is just too dangerous, if you don't really know what you are doing. Fortunatly simple bench power supplies arn't that expensive anymore.


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