Powering a breadboard

[badsign]

Hey folks.

After all the helpful comments on my multimeter post, I thought I'd see what you all had to say about powering my low voltage breadboard circuits. Mostly just stuff from the "Make: Electronics" book for the near term, with possibly some more experimentation with the ESP32 dev boards that I purchased awhile ago.

Multimeter post:
https://www.eevblog.com/forum/beginners/multimeter-purchase-help-request/

Currently I've got a 9v battery and some multicolored jumper wires (male to male, male to female, female to female) and it gets the job done but it's something I think I can improve on for not much money.

Here's a few cheap options I've found that look interesting. All amazon links, so I know I'll be paying a premium but if I can get the solution in hand within a few days it's worth the few extra bucks imo.

USB-C powered module with switch for 3.3v or 5v. Could attach it one of my power banks and be good to go.
https://www.amazon.com/LONELY-BINARY-Breadboard-Power-Supply/dp/B0FXL6DLB9

USB or barrel jack powered module. Comes with some 9v battery - to - barrel jack connectors. Looks like I could power it from a 9v battery, usb to my power bank, or a 9v power supply which I have a handful of lying around including one with a power selector and multiple tips.
https://www.amazon.com/WWZMDiB-Breadboard-6-5-12V-arduino-Battery/dp/B0CDBLG2PJ

Same as above but with some extras.
https://www.amazon.com/Breadboard-Minidodoca-Alligator-Raspberry-Electronic/dp/B0BP9V6WXX

This looks really cool but there are 3 options to choose from and I don't know if this does what I think it does.
https://www.amazon.com/Converter-Fast-Charge-AFC%EF%BC%8CPortable-Regulator-Electronic/dp/B07V3L4YF3

Super basic 9v battery connectors. Cheapest option, but not sure I trust that those leads are going to be able to consistently insert into the holes on the breadboard.. they look really thin.
https://www.amazon.com/Battery-Connector-Leather-Housing-Connection/dp/B06X8YZJ64

I understand there are 'proper' bench power supplies out there and I'm happy to discuss those when the time is right. As far as I can tell, I don't really need something like that yet, which is good because it will give me time to learn and research and ask better questions when the time comes.

And I've seen some suggestions that making your own bench power supply is a good project (for beginners?) so that could be another option after I get something basic setup.

Alright, let me know what you guys think about these options and anything else you have on your mind about powering small electronics projects!

[BILLPOD]

Good Morning Badsign,  Of the choices you presented, I like this one the best:  https://www.amazon.com/WWZMDiB-Breadboard-6-5-12V-arduino-Battery/dp/B0CDBLG2PJ
     But a better choice, and what I use, is a bench top PSU with adjustable voltage and current, so you can limit the current to a maximum that won't harm your breadboard, or anything on it.

[ledtester]

I would recommend any of the ones with a barrel jack input. (withdrawing recommendation based on my follow-up post)

However, consider doing this:

- Get a Lm317 regulator module like any of these:

https://www.amazon.com/Adjustable-Voltage-Regulator-4-2-40V-Converter/dp/B0F2YB668F/
https://www.amazon.com/Adjustable-Converter-Circuit-Regulator-Rectifier/dp/B0DWDM3K13/
https://www.amazon.com/Adjustable-Voltage-Regulator-Mounting-1-25V-28V/dp/B0C3QKRT3Q

Here is a video on how to use them:

LM317 voltage regulator tutorial: how to use a buck converter step down module for DIY electronics -- DIY Electronics
https://youtu.be/XWOfDQLGtVs

Then you use any wall-wart you have lying around and you have an adjustable power supply. (Note that the output of the wall-wart needs to be 2 to 3V higher than your selected output voltage.)

You'll want to mount everything on a board to keep things in place.

[ledtester]

Note that there have been reports of the 5V regulator failing on these breadboard power supply boards:

(at 2:16 in the video)

Breadboard Power Supply Modules on a Budget -- TheElectroBench
https://youtu.be/3lSuT4DW2jA?t=2m16s

That video is from 2020 but this Amazon review from 2025 (also attached below):

https://www.amazon.com/gp/customer-reviews/R1ELIVCY84QDOA/ref=cm_cr_dp_d_rvw_ttl?ie=UTF8

[tooki]

I got some of those breadboard power supplies, and then found that I never, ever use them. I just end up using my bench supply. Being fully variable, and current limited, is extremely useful. Until I had more than one bench supply, I did use two 9V batteries for bipolar op-amp circuits.

[badsign]

Note that there have been reports of the 5V regulator failing on these breadboard power supply boards:

(at 2:16 in the video)

Breadboard Power Supply Modules on a Budget -- TheElectroBench
https://youtu.be/3lSuT4DW2jA?t=2m16s

Wow good find. Thanks for digging in and finding this.

I would recommend any of the ones with a barrel jack input. (withdrawing recommendation based on my follow-up post)

However, consider doing this:

- Get a Lm317 regulator module like any of these:

https://www.amazon.com/Adjustable-Voltage-Regulator-4-2-40V-Converter/dp/B0F2YB668F/
https://www.amazon.com/Adjustable-Converter-Circuit-Regulator-Rectifier/dp/B0DWDM3K13/
https://www.amazon.com/Adjustable-Voltage-Regulator-Mounting-1-25V-28V/dp/B0C3QKRT3Q

Here is a video on how to use them:

LM317 voltage regulator tutorial: how to use a buck converter step down module for DIY electronics -- DIY Electronics
https://youtu.be/XWOfDQLGtVs

Then you use any wall-wart you have lying around and you have an adjustable power supply. (Note that the output of the wall-wart needs to be 2 to 3V higher than your selected output voltage.)

You'll want to mount everything on a board to keep things in place.

I like this idea a lot. I would need to also acquire one of those barrel jack receptacles with the leads coming out so I can hook the power supply into the LM317 device. Not sure what it's called.

Question for you... I see the guy in the video adjusting the screw while current is applied. I noticed he didn't touch anything with his hands, but he didn't explicitly say not to. Probably a dumb question but I'm guessing I'd definitely not want to handle that little thing while it was receiving current?

Edit: looks like I found the barrel jack connectors. Here's a few options that look promising.
https://www.amazon.com/exgoofit-Pigtail-Connector-Connectors-Security/dp/B0D8BDX6Q5
https://www.amazon.com/California-JOS-Male-Female-2-1x5-5mm/dp/B0CR8TZ41W
https://www.amazon.com/DAYKIT-Female-2-1x5-5MM-Adapter-Connector/dp/B01J1WZENK

[tooki]

Question for you... I see the guy in the video adjusting the screw while current is applied. I noticed he didn't touch anything with his hands, but he didn't explicitly say not to. Probably a dumb question but I'm guessing I'd definitely not want to handle that little thing while it was receiving current?

The little buck converter? Nothing hazardous (to humans) about adjusting them while on. It's a good idea to disconnect your load so you don't fry it if you accidentally set the voltage too high.

[badsign]

Question for you... I see the guy in the video adjusting the screw while current is applied. I noticed he didn't touch anything with his hands, but he didn't explicitly say not to. Probably a dumb question but I'm guessing I'd definitely not want to handle that little thing while it was receiving current?

The little buck converter? Nothing hazardous (to humans) about adjusting them while on. It's a good idea to disconnect your load so you don't fry it if you accidentally set the voltage too high.

Good to know. Figured a stray finger touching the wrong thing could be a bad idea but glad to know its mostly harmless.

[tooki]

Question for you... I see the guy in the video adjusting the screw while current is applied. I noticed he didn't touch anything with his hands, but he didn't explicitly say not to. Probably a dumb question but I'm guessing I'd definitely not want to handle that little thing while it was receiving current?

The little buck converter? Nothing hazardous (to humans) about adjusting them while on. It's a good idea to disconnect your load so you don't fry it if you accidentally set the voltage too high.

Good to know. Figured a stray finger touching the wrong thing could be a bad idea but glad to know its mostly harmless.

Up to 120V DC or 50V RMS AC are considered "extra-low voltage" and basically nonhazardous to touch for a healthy adult. For children, 60V DC or 25V RMS AC are recommended.

So the ~30V of a typical bench power supply (or even the 40V maximum input of those buck converters) is far below any hazardous voltage.

[badsign]

- Get a Lm317 regulator module like any of these:

https://www.amazon.com/Adjustable-Voltage-Regulator-4-2-40V-Converter/dp/B0F2YB668F/
https://www.amazon.com/Adjustable-Converter-Circuit-Regulator-Rectifier/dp/B0DWDM3K13/
https://www.amazon.com/Adjustable-Voltage-Regulator-Mounting-1-25V-28V/dp/B0C3QKRT3Q

I noticed that two of them accept AC and DC in, and one of them is only DC in. All of them are DC out. I'm guessing I should go with one of the AC/DC in modules?

[ledtester]

I would just start with the DC in version - unless you have some wallwarts from 10+ years ago which output low-voltage AC power.

You can use a DC wallwart with an LM317 module that accepts AC in but there will be an additional voltage drop (so you'll need 4V over your desired output voltage).

[badsign]

I would just start with the DC in version - unless you have some wallwarts from 10+ years ago which output low-voltage AC power.

You can use a DC wallwart with an LM317 module that accepts AC in but there will be an additional voltage drop (so you'll need 4V over your desired output voltage).

Got it. Snagged the DC version, some barrel connectors and some 22 AWG solid core hookup wire. Should be up and running in no time. Thanks for the assist!

[Doctorandus_P]

I make custom cables to interface with my breadboards.

The simplest is a 2x5 male header that fits in one of the power rails of the breadboard. With 10 fat square pins it fits snugly in the breadboard and can tolerate some wiggling of the cable. I have also soldered a sturdy GND loop (made from 1.5 square mm copper wire). This is very handy for attaching the scope GND clip and for (un) plugging the header from the breadboard.

A more sophisticated version is made in the form of a DIP8. It has a similar GND loop, and it gets both power and data (Serial / RS485) from and to the breadboard.

Breadboards get more unreliable when wires move. If you work with a 9V battery, then it helps a lot to glue the breadboard on a piece of plywood (plastic sheet, whatever) and then also mount the battery to the same piece of wood. The battery can be hold in place by tying it down with a piece of string, a blob of (hot) glue or by gluing some velcro to it. The thin wires of a 9V battery clip are a nuisance for a breadboard, but they can be soldered easily to a dual row header too.

[Doctorandus_P]

One problem with the wide adapter boards that have pins for both power rails in a breadboard, is that the width of a breadboard is not standardized. They do not always fit.

It's quite easy to make a reusable breadboard module with an LM317. Just solder it and it's supporting parts on a piece of matrix (Vero) PCB, and add the same square header pins.