low-cost variable power supplies - Page 1
Forum section: electronics / testgear

author: drakke
author_rank: Regular Contributor
timestamp: January 12, 2015, 11:35:20 am
content: I am just getting into microcontrollers. I don't want to make my own PS and I want something that is safe to me and will not damage my circuits. A local company is selling some basic variable power supplies for very low cost but they seem to have voltage spikes. I don't need a lot of features but I want something that is safe and reliable. I would like to spend around $100-$150.I found these which seem to be suitable from Circuit Specialists.What is a good power supply for a beginner among these:http://www.circuitspecialists.com/csi-power-suppliesThanks.

author: nanofrog
author_rank: Super Contributor
timestamp: January 12, 2015, 07:38:34 pm
content: I'd recommend taking a look at used bench supplies instead, particularly triple output models (more value for your money).You do have to be careful of course, but you can get a good, fully functional supply within your listed budget (happens to be well built, and has decent specs it can actually meet).Here's a few examples:BK Precision 1651HP 6235A, w/ Opt. 28HP 6235APower Designs TP340A(this one needs some meter switches)BK Precision 1651(second unit)Systron-Donner/Trygon TL8-3Most have high amounts of feedback, but not all, and it's a mixed bag as to whether or not the seller has a return policy. That said, I think there are some gems in this group (you're living in Canada made this a bit harder due to fewer choices).Hope this helps, and good luck.*edited to get links from eBay.ca for more accurate prices & shipping fees.

author: retiredcaps
author_rank: Super Contributor
timestamp: January 12, 2015, 09:33:17 pm
content: Quote from: nanofrog on January 12, 2015, 07:38:34 pmEven if they have a return policy, return shipping to the seller is likely to leave the OP out close to $50 USD s/h.OP might consider getting a quality used brand name one locally off kijiji?PS. Note that UPS (brown) and FedEx will charge Canadians a "brokerage" fee charge of $35 USD or more.

author: drakke
author_rank: Regular Contributor
timestamp: January 12, 2015, 11:46:35 pm
content: Quote from: nanofrog on January 12, 2015, 07:38:34 pmThank you. I will look into these.Shipping and other fees almost double the price of these items so I will try to find locally.

author: Lightages
author_rank: Unknown
timestamp: January 12, 2015, 11:53:50 pm
content: If you only need a single voltage, iloveelectronics on the forum here has helped a few members get a nice little power supply, including me.http://gophertc.com/en/ceHis price is right and I have looked at mine fairly closely and it works very well. It also has a lock feature to keep the settings as set in case something gets bumped. PM him and ask.

author: nanofrog
author_rank: Super Contributor
timestamp: January 13, 2015, 12:01:13 am
content: Quote from: drakke on January 12, 2015, 11:46:35 pmNothing in the price range I was searching came up as located in Canada.Single and dual supplies would also be an option (I only searched for triple output models, as they're much better value IME, and commonly available in the US at affordable prices). Shipping on linear supplies does tend to be high due to the weight associated with the metal used to make it (transformers & heat sinks).Regarding local suppliers, you could try used T&M equipment dealers in Canada (may require shipping, but eliminates the import duties and such associated with importing from the US).

author: retiredcaps
author_rank: Super Contributor
timestamp: January 13, 2015, 12:26:42 am
content: Quote from: nanofrog on January 13, 2015, 12:01:13 amYep, the quality and quantity of used gear selection from Canadian ebay sellers is very slim. I know because I look daily. Shipping within Canada can also be very high.When something used does show up, the seller wants almost the same price as something new.

author: eas
author_rank: Frequent Contributor
timestamp: January 13, 2015, 02:37:00 am
content: What are the voltages for the MCUs you are working with? Are you using dev-boards that have a voltage regulator, what range of input voltages do they support? I assume the current/power requirements are going to be pretty low.For very low budget, it seems like an ideal situation to re-use switchmode power supplies from electronics, etc. I've been getting by with various USB chargers for 5v, an Xbox PSU for 12V, and for other voltages, I've been using a "b3603" DC-DC converter fed by a laptop power brick.

author: rx8pilot
author_rank: Super Contributor
timestamp: January 13, 2015, 02:47:01 am
content: I got some of the low-cost supplies from Circuit Specialists about 18 months ago. They got me through some projects and they were less than $100 each. The adj pots got scratchy after a while put can be easily replaced with one high quality multi-turn pot for better control. I soon discovered the value of the HP/Agilent/Keysight supplies on eBay. I picked up a pair of 6653A's and they are AWESOME supplies with terrible displays. I doubt you need 15 amps, and there are many models in that family that are a better size for MCU experiments. They are FAR cleaner than a cheap switching supply from a random Chinese manufacturer.My Circuit Specialist supplies are on emergency backup only status.

author: Fsck
author_rank: Super Contributor
timestamp: January 13, 2015, 02:51:02 am
content: you should be able to grab an e3610 for around your upper range of 150.

author: aviphysics
author_rank: Contributor
timestamp: January 13, 2015, 04:05:19 am
content: Quote from: wilfred on January 13, 2015, 02:56:21 amThat can work in some cases, but it doesn't let you test for performance across a range of battery levels. I have been pretty happy with a very cheap bench supply I got shipped direct from china. I think it was $40, or something like that. My only gripe with it is that the noise level is slightly higher than I would really like for one noise sensitive project. For that, I used an RC low pass filter with a large C and small R. For a low power circuit, the voltage drop across the resistor can be pretty small.In other cases I will use the bench supply to power the voltage regulator I plan to use in the final device. This also helps make the performance of the PSU less important.All that said, I would jump on a quality multi-voltage PSU. It would definitely make things a little easier.

author: zapta
author_rank: Super Contributor
timestamp: January 13, 2015, 04:47:28 am
content: Quote from: Lightages on January 12, 2015, 11:53:50 pmI like it, compact and good range but doesn't do 110VAC. Franky, how does this work, we see something interesting and ask you? Is it limited just to a list of partners you work with?I am looking for a compact bench power supply. I don't need much, 7V 1A is more than I need, but I like it to be small, clear V/A display and reasonably clean power.

author: drakke
author_rank: Regular Contributor
timestamp: January 13, 2015, 10:10:00 am
content: Quote from: eas on January 13, 2015, 02:37:00 amI am taking a couple of Edx courses and typical voltages I think are pretty small. I think I will go with a simple breadboard PS but the b3603 thing looks good.The HP 6653A someone mentioned will be at least $1k from ebay which is almost my total lab budget at the moment. Eventually I'd like to get an HP so I have one less thing to debug.

author: Wytnucls
author_rank: Super Contributor
timestamp: January 13, 2015, 10:37:32 am
content: Quote from: zapta on January 13, 2015, 04:47:28 amFairly happy with the compact Branson SSP-7080, bought in Hong Kong for less than 150$.

author: Wytnucls
author_rank: Super Contributor
timestamp: January 13, 2015, 10:53:55 am
content: Dimensions in mm (WxHxD) 53.5 x 127 x 330mm / 2 x 5 x 13inchWeight in Kg Approx. 1.9Kgs / 4.2LbsUser manual:http://users.tpg.com.au/users/p8king/files/ssp7080m.pdf

author: dannyf
author_rank: Super Contributor
timestamp: January 13, 2015, 03:29:20 pm
content: QuoteThose guys don't take much current. So some fixed 2.5v/3.3v/5v 3-terminal regulators would be more than enough to handle them.If you insist, I would throw in a variable power supply based on LM317 or AMS1117 in there to help those cases.For example, my main mcu board is often powered by an Apple usb charger + LD1117-3.3v.

author: ion54
author_rank: Contributor
timestamp: January 13, 2015, 04:55:51 pm
content: Did you try Amazon.ca?Usually the shipping is free and you might find something that can serve you. On top is very easy to return if you don't like it or it is defective.I am using this:http://www.amazon.ca/Dr-Meter-HY3003D-3-TRIPLE-LINEAR-SUPPLY/dp/B00C3DGT7K/ref=sr_1_17?ie=UTF8&qid=1421166754&sr=8-17&keywords=power+supplyfor almost 6 months now and works great.

author: Lightages
author_rank: Unknown
timestamp: January 13, 2015, 05:22:08 pm
content: Quote from: zapta on January 13, 2015, 04:47:28 amOOPS, sorry I didn't think of the input voltage!

author: drakke
author_rank: Regular Contributor
timestamp: January 13, 2015, 05:42:02 pm
content: Quote from: ion54 on January 13, 2015, 04:55:51 pmI bought this:http://www.amazon.ca/Digital-Constant-Voltage-Current-Step-Down/dp/B00GYVDSY4/ref=sr_1_1?ie=UTF8&qid=1421145725&sr=8-1&keywords=b3603after watching this video:There are a lot of features for a simple device but it can still put a lot of current through my circuits so I will have to be careful.

author: radioFlash
author_rank: Regular Contributor
timestamp: January 13, 2015, 06:31:22 pm
content: I got the Circuit Specialists CSI5003X5. I ran into an issue where the output would oscillate when I connected it to a small solenoid (the current and voltage readings would wildy swing and the solenoid would heat up very rapidly even though the voltage and current were set pretty low). It turned out that one of the output capacitors had a bad solder joint. I fixed the solder joint and it works fine now. Otherwise the build quailty is OK. This one is advertised as dual output, but that means it has a fixed 5V/1A output in addition to the variable output. The good thing is that you can find the schematic for the supply.Having a true dual rail variable supply is handy if you want to work on op-amp or audio amplifier circuits. For microcontroller stuff, you don't need much power. You might consider building your own using an LM317/LM337, see the Elliot Sounds Products project:http://sound.westhost.com/project44.htm.

author: Rick Law
author_rank: Super Contributor
timestamp: January 14, 2015, 12:27:03 am
content: Quote from: drakke on January 13, 2015, 10:10:00 amThe UI is not very good, but the PSU is not bad. I was using some cheap CC/CV board until of late I switched over to the B3603. Good performance for something so low cost.The noise level is high but it really depends on your source and how much you are bucking (DC volt-drop). I too use laptop "power bricks" and other "wall warts" as source.Why multiple power bricks, you may ask. I found that on my laptop bricks, they are very quiet if you draw close to the designed current. But I usually don't use that much power coming out of the B3603. If I buck a lot but draw very little current, the noise is at its 2nd worst. The worst is overdrawn. When I buck from 19.5V to 7V drawing merely 30mA-500mA, I have seen noise as high as .6V to .7V P2P. So, I use a 12V brick if I am drawing reasonably low voltage (0 to 8V). My 15V (Toshiba) or my 16V (Sony, Fujitsu), or my 19.5V (Sony). I cut the original laptop plug and fitted all these bricks with 5.1mm power plug so I can just swap them easy. Just yesterday, I made a new cable to serial two power bricks. My 19.5V Sony+ 15V Toshiba to give me 34.5V - I needed that to play with recalibrate the B3603 itself.Get use to the UI and you will likely find this a very functional low-grade PSU. Good enough for most use in my opinion.Rick

author: loneoceans
author_rank: Contributor
timestamp: January 14, 2015, 12:38:33 am
content: I posted a review of some power supplies over here with videos and writeups:https://www.eevblog.com/forum/reviews/teardown-review-tekpower-tp3010e-switching-bench-power-supply/If you're just starting out, I think a basic linear power supply should be more than sufficient for you.

author: retiredcaps
author_rank: Super Contributor
timestamp: January 14, 2015, 07:43:21 pm
content: Quote from: Lightages on January 12, 2015, 11:53:50 pmVideo review and teardown of it popped up today. Watching it later tonight.

author: drakke
author_rank: Regular Contributor
timestamp: January 15, 2015, 04:49:57 pm
content: Those Gophert power supplies look pretty clean and solid on the inside. But I think I have seen them somewhere else.I seems that with any piece of equipment it pays to test how it performs before you use it.

author: Rick Law
author_rank: Super Contributor
timestamp: January 18, 2015, 02:38:04 am
content: Quote from: drakke on January 13, 2015, 05:42:02 pmLook at this mini review I wrote on this B3603. Since you already got it,read about the SET key. Carelessness with the SET key can be fatal to stuff you have!Otherwise, good choice. I like this unit.https://www.eevblog.com/forum/reviews/b3603-dcdc-buck-converter-mini-review-and-how-the-set-key-could-be-fatal/

author: ted572
author_rank: Frequent Contributor
timestamp: April 07, 2017, 04:37:46 pm
content: Hello: I posted the GOPHERT CPS-3205E Power Supply Calibration Procedure, Specifications, and general comments on easily improving the LED Display Contrast of any of the different GOPHERT Power Supplies.I highly recommend the CPS-3205E Power Supply as it has been very reliable for me. It is small, lightweight, and inexpensive at ~75 US$.If interested please go to ->https://www.eevblog.com/forum/other-blog-specific/new-2016-gopher-cps-3205c-review-teardown/msg1181084/#msg1181084