Need to know if this psu is good enough for a beginner  - Page 1
Forum section: electronics / beginners

author: Albireo
author_rank: Newbie
timestamp: November 13, 2018, 08:37:41 am
content: Hi,I think a benchy psu would be very handy but can't spend too much on it.I found this one for which I also have a €10 discount code.Do you guys think this is good enough?https://www.eleshop.nl/0-30v-0-3a-labvoeding-met-verlicht-lcd.htmlOr should I go with a 5 amp one like this one?https://m.reichelt.nl/laboratoriumvoeding-0-30-v-0-5-a-gestabiliseerd-rnd-320-kd3005d-p212040.html?&trstct=pol_7Or do you guys have better recommendations?Thanks.

author: t1d
author_rank: Super Contributor
timestamp: November 13, 2018, 09:44:12 am
content: I suggest that you do some study, yourself, on power supplies. It is good etiquette. It is best that you develop the skills to do basic research. After that, we would be glad to help with any remaining questions. But, you certainly need some direction, to even know where to start.Factors to consider1) Type of supply; Linear, or Switching. Each has its place.2) Wattage needed; Depends on the type of work it will be used for. But, 30v and 3a is typical, of basic models.3) Does it have course and fine adjustments?4) Digital readout, or analog meters?5) Does it have Constant Current and/or Constant Voltage?3) Number of Outputs; Single, Double, Triple...4) Quality5) BudgetStart with a search, within this forum. There are other threads on this subject. And, maybe look at some YouTube videos.Let us know, what you discover. Then, for any questions that you have, give us the details, of what you plan to do with it, etc.Don't be discouraged, we will help you. And, I was given this same advice, when I started posting here. It paid off. :-)

author: mvs
author_rank: Frequent Contributor
timestamp: November 13, 2018, 12:36:36 pm
content: Quote from: Albireo on November 13, 2018, 08:37:41 amI would not recommend you to use switching power supply as a first power supply in the lab. You can buy it as 2nd or 3rd one and use for battery charging, etc.QuoteKorad is quite ok for this money. It is digitally controlled (knobs are rotary encoders), linear power supply. There is also a version with more buttons/features (memory, output on/off, etc) available, KA3005.

author: JackJones
author_rank: Regular Contributor
timestamp: November 13, 2018, 12:44:02 pm
content: One thing both of the linked models seem to lack is an on/off switch for the output. That's a really handy feature, personally that's a must for me in a power supply.Reichelt actually has the better version of the Korad (KA3005P) on sale for ~€94 right now. I ordered one on Sunday, personally I would pay a little more to get that one.

author: spec
author_rank: Frequent Contributor
timestamp: November 13, 2018, 06:53:00 pm
content: I use three of these:https://www.ebay.co.uk/i/183449223050?chn=ps0V to 30V (you can never have too much voltage capability)0A to 10A (you can never have too much current capability.Linear design, not switch modeLow noise output (10mV)Simple construction using basic circuitryPrecision Voltage and Current coarse and fine controlsCompact and fit on your bench without taking up too much roomSturdy constructionDigital read out for voltage and currentSilent until fan comes on automatically for high power demand, but then not too noisy.£50UK, but no doubt available in your country (you do not indicate where you are).Why go for anything else

author: cdev
author_rank: Super Contributor
timestamp: November 13, 2018, 07:10:02 pm
content: Make sure you get one with current limiting capacity. Its especially useful when you can dial in an amount with some precision to limit at. Higher voltage than around 15 volts isn't really needed for most of the stuff I do.Also, I rarely need more current than at most a few amps. But the current adjustment is the most useful feature. It pays for itself when you are building things.And the finer the precision the adjustment can be set to, the better.Its also useful when there is some indication of when it trips thats easy to see and/or audible. On my power supply the LED changes color. That's enough, you just want some means of knowing.

author: rstofer
author_rank: Super Contributor
timestamp: November 13, 2018, 07:15:42 pm
content: There are wide variations in what people expect from a power supply. Will your first choice work? Probably. It is inexpensive and might just be a good place to start. I worked for decades with fixed voltage supplies, wall warts and batteries. Sure, my Rigol DP832 is a better way to go but I find myself with adequate funding. That wasn't always the case!Here's why I wouldn't buy that type of supply (regarding the controls): I like current limiting. It saves a lot of chips that otherwise would have gone up in smoke. For those supplies, you basically have to have some adjustable load that you can connect to the power supply in order to set the current limit point. Or, you might be able to set the current limit very low, short the output, and then work it up. In any event, I don't want to work that way.BTW, the DP832 has two current limiting features. The 'constant current' setting is the point at which the voltage will start to fold back as current tries to exceed that point. Then there is 'current limit' where the outputs turn off if the current exceeds the limit. Fold back or trip - very nice features.On the Rigol DP832, there is a digital setting for the current settings (constant current or limit) in the same way there is a digital setting for the voltage. For 10x as much money...Watch the comments for any competing models, drive a stake in the ground in terms of cost, and take the leap. It won't be the best bench PS, it might not be the worst.BTW, 3 output supplies are quite handy and 3 individual supplies don't turn the voltages on at identical times. Maybe a 3 pole switch. Leave the PS outputs on and use an external switch.Everybody has to start somewhere...

author: ArthurDent
author_rank: Super Contributor
timestamp: November 13, 2018, 09:38:12 pm
content: I have nothing against switching power supplies and have both linear and switching power supplies on my bench. You have apparently done some research and have a good idea what you want to spend and there are a lot of power supplies around that price range. Of the two you linked to, I would choose the second. The first only has recessed banana jacks rather than 5-way binding post like the second supply you linked to, making the second one more versatile to connect various loads to. It also has a grounding post on the front. The second also has some other features like OCP and looks like a better buy.While it is true that you could get a much better supply for more $$$, starting out it is better to get a reasonable inexpensive one. As your interests grow over time you can make a better informed decision on your next supply that might be better suited to your needs.

author: james_s
author_rank: Super Contributor
timestamp: November 13, 2018, 10:20:56 pm
content: You'll likely end up with several power supplies eventually, a beginner can get by with almost anything so long as it's safe.Personally I like a power supply with real analog knobs, I've seen some digital models that can lock up and set the output to random values which can obviously be a very bad thing. You might also consider used, there are lots of good linear boatanchors available on the used market.

author: FriedMule
author_rank: Frequent Contributor
timestamp: November 14, 2018, 02:44:59 am
content: As a beginner I would avoid switching mode power supplies because they do often make a lot of electronic noise that can be hard to work around for youngplayers:-)As an advice on wich to choose I would also get a Korad and if you can afford it I would get the ka3305d.

author: rstofer
author_rank: Super Contributor
timestamp: November 14, 2018, 04:15:29 pm
content: As a side issue, you will have more use for a fixed voltage supply than an adjustable supply. In my case, I need +5V more than anything else. Or at least I did in the old days. Today I probably need 3.3V. If I am playing with op amps, I need +-15V supplies but these don't need anywhere near 1A. The 5V probably needs an amp and 3A isn't unreasonable but 1A worth of low power Schottky (74LSxx) is a lot of chips! There is a tendency to create 3.3V on the board so many of my prototype boards take 5V or sometimes 9V. These are usually fed from a wall wart. I have a gaggle of 5V 2A wall warts.The point is, you can build decent linear fixed output supplies for very little money and minimal effort. No, they probably won't have fancy meters but you can always use a DMM in series to measure current and you already know what the voltage is. But you can measure it. Don't overlook inexpensive DMMs for this like the Aneng 8008. This is a really nice meter for low voltage, low current work.I got along for decades without a bench power supply. If I didn't have one I might miss some of the elegant features but an inexpensive supply doesn't have these features anyway.Don't overlook wall warts!

author: spec
author_rank: Frequent Contributor
timestamp: November 14, 2018, 04:43:33 pm
content: Quote from: rstofer on November 13, 2018, 07:15:42 pmIndependent supplies are much more useful and you can just add supplies as you need. They also give the best V/As for the buck. The three supplies I use are typically set to 3V3 or 5V for logic, 12V and -12V for analogue.But other times, I use them for high power audio amplifier work, car ignition and just plain battery charging. And err, power supply design. It depends on what electronics you do. A variable supply can function as a fixed supply, but not the other way around. I doubt that you could make a fixed supply for the cost of one of the supplies I mentioned, and then there would be all the effort.Even multiple PSUs do not switch on at precisely the same time, especially if they have different loads.The answer, as you say, is simply to use a multi pole, high-current switch, or individual relays for each PSU, which are probably the best approach, being modular and dirt cheap.Although you didn't mention it, using a switch also eliminates any turn off delays too.