Is this multiple triple power supply a good buy?  - Page 1
Forum section: electronics / beginners

author: Tech77997
author_rank: Contributor
timestamp: March 17, 2020, 09:30:59 pm
content: How much is this specific model power supply worth it to a beginner who would like quick access to multiple power supply outputs? Are there better options out there for that goal? Anyone know anything in particular about this specific model? Is this model a good buy?https://www.amazon.com/gp/product/B009622HC2/ref=ox_sc_act_title_3?smid=A2KV19AYUKS3X0&psc=1

author: thm_w
author_rank: Super Contributor
timestamp: March 17, 2020, 09:43:38 pm
content: What is your budget.What is requirement for number of channels. This supply is more like a 2 channel and a fixed 5V. To me that fixed 5V is close to useless as the current limit is so high.What is your requirement for current/voltage setting resolution. This is 10mA 100mV.What is your use case. High current heaters/motors or precision circuits (opamp, microcontrollers) or both?If you are looking for cheap with a lot of output current this is probably decent. If you have more money or a specific use case, there may be better options.

author: Tech77997
author_rank: Contributor
timestamp: March 17, 2020, 10:02:41 pm
content: I do not want to spend more than $200 on the power supply. I would like as many channels as possible for my budget. My use case are op amps and microcontroller precision circuits.I am wondering if instead of purchasing 1 triple output power supply, I should purchase 3 single output power supplies. Are there any benefits to that? Or, I am wondering if this one below, for $30 cheaper, would also suffice:https://www.amazon.com/gp/product/B00068UIFI/ref=ox_sc_act_title_1?smid=AMH4W1K8OCGMX&psc=1

author: thm_w
author_rank: Super Contributor
timestamp: March 17, 2020, 10:48:58 pm
content: The only difference I see with that supply is LCD vs 7-segment LED displays, its your preference if that is worth the $30 difference.There are some advantages to having 3 supplies, easier to move around, higher reliability vs a single unit, etc. but cost can be more, more hassle to turn each unit on.For opamps/micros I'd be tempted to get a lower resolution unit. But I'm not sure what exists in that price range.

author: aeberbach
author_rank: Regular Contributor
timestamp: March 17, 2020, 10:59:57 pm
content: I decided on single supplies as you can start with one (or two) on a budget; sure I wanted the new triple with all the bells and whistles. Singles are more compact and easier to move around, as a side benefit. I bought two Tenma 72-10480 when Element14 had a promo on, I like them so far.

author: Tech77997
author_rank: Contributor
timestamp: March 17, 2020, 11:07:39 pm
content: Thank you for your reply, by the way!

author: Tech77997
author_rank: Contributor
timestamp: March 17, 2020, 11:08:23 pm
content: Thank you all for your input.

author: Tech77997
author_rank: Contributor
timestamp: March 18, 2020, 12:54:16 am
content: I am conflicted as to buy a switching or a linear supply, and how to really know how many outputs I really need. I want to work on micro controllers and op amps specifically, but do not want to buy something that will not be useful for future projects. I want to buy something that will last and can be used for many projects- something that I can own for a long time. I do not want to bother anyone and/or take up much of anyone's time. But would anyone give me insight into a specific model (or models, in order to get more outputs if recommended) to buy, since for a beginner the sea of models out there with their varying pricing is quite overwhelming.Thank you so much for your patience.

author: atmfjstc
author_rank: Regular Contributor
timestamp: March 18, 2020, 02:50:55 am
content: I wouldn't worry too much about longevity, since pretty much any cheap power supply is guaranteed to be unreliable over the years. There's a reason why professionals spend big bucks on reputable brand equipment. If you're just starting out, you should expect the supply to be OK for 1-2 years of learning after which you will likely want/have to upgrade it, and you will have likely gained the experience to know exactly what you want and what quality looks like.With respect to choosing between switching vs linear, I can point out a few things from my experience:- Switching power supplies are inherently more complex, so in principle they offer a greater chance of bad design, random failure or unpredictable behavior (not that one can't screw up a linear supply too)- Linear power supplies are MUCH heavier. Most units I've seen weigh around 5kg, the triple-channel one you mentioned weighs 10kg (!) since it probably has 2 transformers. You have to be careful about what you sit it on, and if you drop it, both the supply and whatever it lands on are gonna be toast.

author: Brumby
author_rank: Unknown
timestamp: March 18, 2020, 04:10:51 am
content: There is a real difference between the two supplies originally cited...The first one has two 30V 5A channels while the cheaper one has two 30V 3A channels. (Both have a fixed 5V 3A channel.)If you are working with Op-amps using split supply rails, then a tracking supply (which both of the above are) makes for easier adjustment of both rails at the same time. (You could still do this with independent supplies, but you would adjust them separately.)Linear supplies are, indeed, heavier than switch mode ones since they carry a chunky mains transformer - BUT they do (typically) offer a lot less noise on the output. If you are doing audio projects or low signal level work, switch mode supplies can be a source of annoyance.

author: wizard69
author_rank: Super Contributor
timestamp: March 18, 2020, 04:46:39 am
content: I'm actually surprised at some of the answers to be had in this thread. First off power supplies have for a long time been some of the first projects somebody learning electronics did. It is a great learning experience. You can start with simple 3 terminal solutions and move on from there. I would argue that you don't need a complex power supply to get started.Quote from: Tech77997 on March 18, 2020, 12:54:16 amWhy struggle? Buy something that fits your needs. That is a voltage and current capability that allows you to pursue your intesrests.QuoteYou and I have not idea what those future projects might be. To get started in controllers you can use a wall wart and a three terminal regulator. It really doesn't make sense to spend big bucks here when you can apply that money to other things. Also your experience will later tell you what would be the best fit for your needs in a bench supply.QuoteActually it isn't that easy. Consider this we have some really nice bench supplies at work that you can't buy anymore. The manufacture apparently doesn't exist anymore. I could easily say that this supply:https://www.digikey.com/products/en?mpart=T3PS3000&v=1133meets your goals but it sure doesn't meet your budget. My budget either but that is beside the point.The point is that yo will almost certainly have to go with an off shore brand that doesn't have a track record. As such your only avenue to reviews is the net and here you need to find a respectable site. Or gamble and buy & review yourself. The very first power supply you linked to I had never heard of until this thread. If price is a big concern get on the major supplier sites and do parametric searches by price ( I really don't recommend this as too much of a focus on price leads to the wrong priorities).QuoteBy the way right here on the EEVblog there has been some good reviews of parts to DIY power supplies that come from China. They are prefabbed enough that you can still get a bit of build experience. That is learn something.However my major point here is that if somebody is new to electronics they are simply wasting money if they go out and buy a multiple channel power supply before they even get started. At the very least cobble together a 3 terminal solution to give you a 5 volt source as the stuff you learn here will pay off for decades. Latter build a +-12VDC solution with 3 terminal regulators or combine both of these at once. For the stuff you are interested in you probably be fine with 1-2 amps on the 5VDC rail and 500 milamps on the 12 volt rails. There are four good reasons to do this. 1. You learn about linear regulators, power supplies and transformers in general. 2. You defer spending money on a power supply until much later (you will eventually want one). 3, You learn skills involved in the mechanical assembly of such a device. 4. You will have more money up front to spend on multimeters.#4 is perhaps a big point as in the ideal world you will want at least two multimeters on your bench pretty quick. Equipping a bench is far more expensive than the components you will be working with. As such I see spending money on a fancy power supply right off the bat to be foolish.

author: Urshurak776
author_rank: Contributor
timestamp: March 18, 2020, 12:42:20 pm
content: I'm beginning also and looking at building two bench power supplys. Cheapies big time. That Hiliand/bangood $5 one and an LM317 based one I found on youtube. Both have flaws, but something fun to get started and learn. Even if they both end up in the trash later, not a lot of money wasted and a lot of experience gained (I didn't know what an LM317 was until last week.)That being said, you can get a decent power supply on Amazon for $60 that is fine for a beginner:https://www.amazon.com/dp/B078MY5RGQ/?ref=exp_learnelectronics_dp_vv_d

author: Tech77997
author_rank: Contributor
timestamp: March 18, 2020, 12:46:41 pm
content: Thank you for your very detailed reply. Your insight is incredibly appreciated and very helpful.I will heed your advice. As a clarification, would this satisfy what you said about using a wall wart:https://www.amazon.com/HiLetgo-Supply-Module-Prototype-Breadboard/dp/B00HJ6AE72/ref=sr_1_1_sspa?crid=3OPCH09O7IV2L&keywords=breadboard+power+supply&qid=1584534822&s=electronics&sprefix=breadboard+p%2Celectronics%2C-1&sr=1-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzNzVOQTRDTzVSMjcyJmVuY3J5cHRlZElkPUEwODM2ODUwMVVVUU8zMkdBQ0k3NCZlbmNyeXB0ZWRBZElkPUEwODY1OTAxMksyMTRYQ0pMRTJUUyZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=Also, I have now decided to build my own power supplies as beginner projects. I know this one is a kit, but would you say this kit is worth it?https://www.amazon.com/Elenco-Triple-Output-Power-Supply/dp/B0002DT0GU?ref_=fsclp_pl_dp_3Of course, building from scratch from schematics- as Dave's series goes in depth in- is something I will mainly strive to do, but I do know he recommended some kits. That Elenco kit is really the only kit I can find nowadays, I cannot seem to find many kits out there; the ones Dave showed in his "How to Set Up and Electronics Lab" were from Silicon Chip. I know another post on this site from a few years ago asked about this, but many of the links that people posted in that thread led to discontinued kits.Many thanks again for all of your help.

author: Tech77997
author_rank: Contributor
timestamp: March 18, 2020, 12:48:26 pm
content: Many thanks to everyone's help here.

author: rdl
author_rank: Super Contributor
timestamp: March 18, 2020, 05:39:27 pm
content: I built a couple of Elenco kits years ago. They were decent quality with good instructions. Don't use the solder they provide. Get some 60/40 or 63/37 leaded solder. Make sure it's for electronics and not plumbing. You'll probably want to add some kind of metering eventually, which means experiencing the joys of cutting rectangular holes in a metal panel.When building from scratch, I like the Avel-Lindberg toroidal transformers sold by Parts-Express. They have some 15 and 30 watt that are well made, safety approved and not terribly expensive.I built a basic LM317 based supply when I first got started and it was all I need for years.

author: wizard69
author_rank: Super Contributor
timestamp: March 18, 2020, 09:24:42 pm
content: Quote from: Tech77997 on March 18, 2020, 12:46:41 pmActually not at all. A wall wart in its original slang from was a transformer based power pack that plugged directly into an AC outlet with a low voltage lead going to what ever it powered. Basically it provided a manufacture or builder with a reduced voltage for his device. The packs came in AC and DC versions of different voltages.The nice thing about a well engineered wall art is that you don't come into contact with high voltages. The negative is the lack of power. However to get started with microcontrollers you don't need lots of power. Modern wall warts often look just like the old ones but use switch mode power supplies, some of these from China are pretty bad. Still a working wall wart solves about 50% of a low end power supply build.QuoteMaybe, it is hard to comment on things you don't have and never have seen. The problem is it isn't dirt cheap. In any event a less that 30 second search on the net came up with these guys:http://www.mastechpowersupply.com/linear-power-supply.htmlThe reality is the cost of a kit is hard to justify anymore and is one of the reasons the great name of Heathkit suffered so much. With modern production methods it is actually cheaper to ship a completed power supply than to ship a kit to a customer.Now the thing here is that the kit you posted might actually be of higher quality. I really don't know. What I do know is that you will lean more by taking the manufactures data sheet for a three terminal regulator and scraping up the parts you need to build a power supply for your microcontroller. Kits are great due the all in one bag concept but that bag doesn't hold the knowledge that went into it. By skipping the bag you afford yourself the opportunity to learn many things. That includes salvaging parts, learning how to read data sheets ( at least the readable ones), learning to order parts and actually find them online. You might even find local sources, for new, used and surplus "stuff".Quote

author: Doctorandus_P
author_rank: Super Contributor
timestamp: March 19, 2020, 02:16:38 pm
content: Most of the power supplies I see here are pretty high power and low resolution.For regular electronics work something like 20V 1AmA is usually enough.For electronics work you also want fairly accurate voltage settings and a few extra digits in the current measurement. For current I would at least want a 1mA resolution. 100nA would be preferable.There is quite a gap between those affordable but simple power supplies, and something like a Keithley 2400.As a starter I advise to start with a few of the Hiland power supply kits with an ATmega and a HD44780 display. They're not great but they are usable and they can be a base for lot's of mods from writing your own firmware to adding better ADC's and opamps for better set-points and measurement.Another fun mod can be to add one of those ubiquitous LM2596 boards and a few small components as a pre-regulator.

author: Yansi
author_rank: Super Contributor
timestamp: March 19, 2020, 02:34:37 pm
content: If you have $200 to spend, buy for example a used Hewlett Packard E3630A and E3610A. You will thank me later.All of the above mentioned Amazon PSUs regardless of LCD or LED displays are the same lowbidder crap. The typical style of the power button and terminals and the style of the front panel is a dead giveaway they all come from the same OEM. Had one of those (only the single 30V 3A version I think). Utter crap! Do not buy.Buying a couple Korad KA3005 PSUs would be way better choice anyway.

author: Yansi
author_rank: Super Contributor
timestamp: March 19, 2020, 02:38:13 pm
content: Quote from: Doctorandus_P on March 19, 2020, 02:16:38 pmWhat designer does depend his work on the crappy panel meters included in those power supplies? These hold only INFORMATIVE values. You use different instruments for precision measurements.1mA current meter resolution is definitely handy, but shall not be a requirement for a cheap and generic PSU for a beginner.And if you need a precision power source, you are not looking at $200 cheap amazon PSU anyway, you want something like a Keithley SMU.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: March 19, 2020, 03:05:48 pm
content: Quote30 year ago you were right in this, but in the mean time electronics have improved a lot.Everybody wants his power supplies to have at least half decent meters. In these days it's just silly to use 2 DMM's just to monitor the voltage and current for each of your power supplies.OP wrote he's mainly interested in opamps and other low powered circuits, and 30V5A with low resolution meters is not the best power supply for that.There are some decent and affordable power supplies "out there" but they are hard to find, but most power supplies seem to be either very cheap and low resolution, or SMU like and prohibitively expensive. This is probably one of the main reasons home built power supplies are still worthwhile.Using all your DMM's just to measure voltages and currents of your power supplies is a wiring mess and a nuisance, while being able to see that your opamop circuit suddenly uses 60mA instead of the 40mA that it did for the last 2 weeks is very informative of something being wrong.I am really having trouble in understanding the use of these power supplies. I would either want some high power power supplies for motor circuits and replacement for LiPo packs on my desk, or something for powering electronics and in the second case at least 1mA reliable resolution is mandatory. I bought a cheap Gophert CPS-3205 (32V 5A) some time ago, and it's barely usable. I bought it because of it's 1mA resolution, but it can easily be 20 counts off.

author: Yansi
author_rank: Super Contributor
timestamp: March 19, 2020, 05:05:41 pm
content: You seem looking for problems where they do not exist in the first place.Especially for the mentioned OPAMP work, OPAMP a) does not give rats ass whether you have 12.073 or 12.000 V b) you are rarely interested in the current consumption to the last mA. So a requirement for 10mV/1mA resolution meter is just nuts. *And if you happen to really care about current consumption or specific voltage, it is exactly when a precision meter enters the game - not an integrated meter in a cheap power supply.Sure, electronics have improved a lot, thats why one can buy a 5 digit LED display chinese panel meter, thinking how great of a deal he got for $1.5 yet to later find, the crap drifts like crazy, has offset of up to +-30 counts and has a pretty bad nonlinearity, so just the first 3 digits out of 5 are in fact usable.So, unless doing some pretty specific tasks, you absolutely DO NOT need either a precise nor fine resolution meters on you power supplies.Not even to start talking about the fact that resolution below 100mV is pointless anyway, unless using 4 wire connection to the load.Heck even a power supply with analog needles is ENOUGH for most hobby work.You seem to be fixated on shiny blinky displays, neglecting the fact there are way more IMPORTANT parameters a lab power supply should have, even for a beginner hobby work.*EDIT: To clarify, one needs a good resolution of the controls, ie. a vernier potentiometers (or the annoying COARSE-FINE combo I truly hate) to be able to fine adjust parameters, but rarely you do need precision meters.

author: rdl
author_rank: Super Contributor
timestamp: March 19, 2020, 08:14:14 pm
content: Some people like their power supply to do double-duty as a DMM. Most of the time better than 10 mA resolution is not necessary. Actually, many times simply the trend is all that's needed, which is hard to see with digital ammeters. This is my daily driver. It's not perfect, but if you can find one in good shape for under $150, give it a shot.I also have a couple of the E3610A. If you are ever tempted to buy one of those, try to get an Agilent branded one, or later model HP. Most of the problems were fixed by then.Finally, if building from scratch is tempting you, read this:http://artofelectronics.net/wp-content/uploads/2016/02/AoE3_chapter9.pdfEarly in the chapter they provide a nearly complete schematic for a decent starter lab power supply.

author: wizard69
author_rank: Super Contributor
timestamp: March 21, 2020, 10:36:04 am
content: I’m still of the opinion that a beginner should do the first few microcontroller projects with DIY supplies. It is simply part of the learning process. The quality of the various bench supplies isn’t an issue here but rather the value is learning about the electronics of microcontrollers and approaches to powering them.The whole thread bothers me due to the fact that i had very little in the way of instruments when first getting into electronics. I just don’t see the point in focusing on instruments that don’t offer a lot to the beginner. Any money allocated to a bench supply would be better spent in n a decent DVM or two, an Oscope or similar.

author: GerryR
author_rank: Frequent Contributor
timestamp: March 21, 2020, 11:48:59 am
content: Anyone working in electronics needs some basic equipment, a good power supply, preferably triple output with tracking, a good multi-meter 4-1/2 digit or better, and a decent scope. Good equipment avoids a lot of frustration, especially while learning. If you find your requirements change as you get more experienced, you can always sell and trade up to your needs. Trying to learn with less than adequate equipment is not an option to me, just a frustration. I have never seen a college lab or technical school lab with junk equipment to help their students to learn. Just my $.02.

author: Brumby
author_rank: Unknown
timestamp: March 21, 2020, 11:11:30 pm
content: Quote from: GerryR on March 21, 2020, 11:48:59 amWhile these are good things to have and as you progress through your interest may become preferable, they are not usually essential - especially in the beginning. All the greybeards here would have run their early years with a 20k/V analogue meter. A 4-1/2 digit DMM is not indicated for someone starting out.QuoteYour point is understood - but I would like to balance that by including my perspective ... that bynothaving all the fancy gear, you are forced to think harder about what is going on. Yes, this can be a source of frustration, but it can also be an enabler for a deeper understanding - especially of the basics ... and if you haven't grasped the basics, then adding high functionality equipment is just going to make for even more confusion.Specifically:* Triple power supply. Nobody will argue it's a nice thing to have - and anyone who gets one won't be the worse off (except, possibly, in the wallet). However, how often has this been a necessity, especially when first starting out? Tracking is rarelyessential, but can beconvenientif you're doing work with Op-amps.* 4.5 digit DMM. Again, a nice thing to have, but a 3.5 digit meter is, I maintain, more than enough for over 99% of measurements - even today.* "Decent" scope. Yes, if you do get a scope, a decent one is where to think - but what is "decent" will depend on your use case. I wouldn't advocate the DSO138 in any seriousness, but it can be useful in the right setting. Nevertheless, many things can still be done without the need for a scope - but, I will concede, modern projects with microcontrollers may find a scope (or logic analyser) helpful, as long as the user knows how to drive it.

author: GerryR
author_rank: Frequent Contributor
timestamp: March 22, 2020, 11:33:41 am
content: Being a 70 yrs. old "greybeard" myself, I understand where you are coming from. However, the OP stated the following,"I do not want to spend more than $200 on the power supply. I would like as many channels as possible for my budget.My use case are op amps and microcontrollerprecisioncircuits. "I'm just trying to help him avoid the frustrations of inadequate equipment; been there, done that. I will agree that not having certain gear can make one very resourceful, as you can't always afford a specialized piece of equipment to do a job, but you do need the basics, power supply, meter and 'scope.

author: Tech77997
author_rank: Contributor
timestamp: March 25, 2020, 01:03:50 am
content: Many thanks for all of your input! It is so very helpful as I learn. I am amazed at the amount of replies. I will carefully consider all of the input.Thank you again!

author: Jwillis
author_rank: Super Contributor
timestamp: March 25, 2020, 07:45:37 am
content: Quote from: Tech77997 on March 25, 2020, 01:03:50 amThat supply in your OP is a rebranded Mastech HY3005D-3 . There have several brands like VOLTEQ and Dr.Meter. These models have been around for some time now and the $184.99 now is much better than the $400 I paid for mine a few years ago. They are alright and stand up to the kind of abuse I dish out. Mine needs calibration a little because the readouts are out by 100mV and about 20mA . But it has maintained stability quite well even after many times at full loads. For lite to average loads it will probably give you a few years of good operation. They are not fancy and don't have digital settings or memory.If something does go wrong there are plenty of schematics available and the parts are all common components.