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Project Notes

#060 5V Breadboard Regulator

An LM7805 5V regulated power supply on breadboard-compatible protobboard.



See LM7805 5V Regulated Supply for a more detailed investigation of the 7805 voltage regulator.

The LM7805 provides regulated 5V, ideal when current requirements are moderate (up to 1A with heatsink).

This project puts a 5V regulated supply on a protoboard that is designed to plug into a standard breadboard with power rails.

It includes high and low frequency smoothing capacitors, and a master power switch and LED power indicator.

The LED indicator is provided on the regulated supply-side. The 3mm green LED has a forward voltage drop of about 2.2V, so a 1kΩ current-limiting resistor was selected to keep current draw approx 2.8mA.

Given that commercial units can be obtained for as low as 0.80USD (with free shipping!), I’m not sure if I saved any money. But it is more satisfying this way;-)




Sketching a protoboard layout that would work:

Protoboard layout Build

Testing - within a few mV of 5V as expected:


Credits and References

Project Source on GitHub Project Gallery Return to the LEAP Catalog

This page is a web-friendly rendering of my project notes shared in the LEAP GitHub repository.

LEAP is just my personal collection of projects. Two main themes have emerged in recent years, sometimes combined:

  • electronics - usually involving an Arduino or other microprocessor in one way or another. Some are full-blown projects, while many are trivial breadboard experiments, intended to learn and explore something interesting
  • scale modelling - I caught the bug after deciding to build a Harrier during covid to demonstrate an electronic jet engine simulation. Let the fun begin..
To be honest, I haven't quite figured out if these two interests belong in the same GitHub repo or not. But for now - they are all here!

Projects are often inspired by things found wild on the net, or ideas from the many great electronics and scale modelling podcasts and YouTube channels. Feel free to borrow liberally, and if you spot any issues do let me know (or send a PR!). See the individual projects for credits where due.