Noob Breadboard Question

Thread Starter


Joined Jul 12, 2011
Hey guys, I bought a multimeter, breadboard, jumper wires, and a few resistors to start dabbling in making a circuit. I was wondering how to supply it with voltage. How would it work? Do I just tape batteries to the jumper wires and insert the wires into the bus of the breadboard or what?


Joined May 3, 2010
Easiest way would be to get a battery clip (for 9V) and plug those wires into your V+ and GND buses. Make sure to limit your current with appropriate resistor values, when using batteries, so that you don't drain them quickly or have large currents flowing around.

Most phone chargers are 120VAC to 5-6VDC, (here in North America at least), so you could grab a couple of those and strip the plug off to use that as a power source.


Joined Mar 24, 2008
I do a lot of work with protoboards, even write articles about them. Volume 6 of the book (links on top of this page) has a nice selection of experiments on various projects. Click on them sometime.

My favorite is a simple 9V battery and clip. But you can also get battery holders in every size. AA batteries are the cheapest out there. With the right battery holders you can make 3V, 4.5V, 6V, and 9V. They have a decent current source too.


Joined Jul 7, 2009
You can also go to a second-hand store and pick up used wall warts for 25 cents to $1 each. Note many of these are unregulated. I've found that HP wall warts intended for laptops are well-regulated and light weight; I've got an F1044A that is 12 V 2.5 A output and its output voltage only drops a couple of percent from no load to full load output. This would make an excellent little DC power supply for experiments, especially if it was used with a suitable regulator for making an adjustable output voltage.


Joined Sep 9, 2010
Another good choice is to pull the power supply from an old computer. These can be had for free, and any of them supply several amps at 5v, 12v and maybe up to 1A at -12v (handy for many op-amp experiments). The enclosure for an old hard drive will have a similar but smaller supply. I like to use the PSU from an old Mac, since they didn't use fans and are silent. A PSU is overkill for breadboard circuits but can come in handy if you're also playing with relays, light bulbs, fans and such that might draw more current.

Beware of unregulated wall warts. The high peak voltage (much higher than the rating on the case) can be a problem, but the ripple will also play havoc with many circuits.