Hello there and welcome to this blog post about how to build a  simple 5v power supply, Most electronic component, logic circuits and micro-controllers/processors require a clean and stable 5 volt power supply to work, some may be flexible to work with a range of voltages; say from 4v to 13v, whereas others are a bit sensitive and choosy they require 5v with little to no tolerance, so one has to be careful of what he is feeding his device

To build a stable power supply there are many topologies to consider this will greatly go a long way in determining the size, cost, reliability, and speed of production the majority of the topologies used today are linear and switching mode power supply (SMPS). To build help you choose which topology is best suited for your project here are some of the things to consider.

  • The target device: some device are noise sensitive and will not work well with noisy power supply whereas others are not.

  • Budget yes budget determines the type of component one chooses

  • Efficiency the efficiency of a power supply matters especially in battery operated devices

  • Output voltages, multiple or single output voltages play an important role

  • Time for complete product

Refer to the table below for a simple comparison chart to help you choose a power supply topology.



Output voltage/s


Time for complete product











For simplicity, I considered only two topologies that are linear and switching mode power supply but there are other power supply topologies like resonant transition switching regulator and quasi-resonant switching regulator which are a bit too complex. Comparing the table above clearly linear topology seems fair it is cheap fast to produce thought it has low efficiency but it will do for the main time. Now zeroing on linear power supply how do we go about it? What and what is required? Actually, this is not as complex as it may sound; thanks to large scale integration (you can read about it here) we have dedicated ic’s that just that like the lm317 and l78XX which are both linear regulators. Both the lm317 and l7805 are three terminal devices with input, ground, and output. Linear regulators work by simply burning off excess voltage as heat, to put simply you input a higher voltage it outputs a lower voltage and burns off any excess voltage as heat, so it can be seen as a step down only. The input of the linear is always expected to be greater than the output. The LM317 is a variable step down voltage regulator with minimal component count one can get the desired output voltage with a constant current of 1.5A. The 78XX series is a fixed value linear voltage regulator with a current of about 1A. Today we will start with the 7805 and build a simple 5v power supply, and then, later on, we shall also build a 5v power supply using lm317. So today the component needed are;

  • L7805

  • 100uf capacitor

  • 100uf capacitor

  • 9v battery

  • Dc Jack

  • breadboard

  • multimeter

let’s take a look at the schematic diagram first

a circuit diagram of linear 5 volt supply

The circuit is simple and straight forward doesn’t require any soldering so everybody should be able to follow just fine. From the far left is a 9v battery whose voltage is fed to the voltage regulator through a 100uf capacitor, this capacitor is known as an input capacitor it helps in eliminating any noise in the input line for most cases. Both the input and output capacitors are needed else switching a relay could reset a micro-controller.

For practical purposes where a load which is greater than 500ma is applied at the output, it is always advisable to use a heat sink. Thanks for reading visit again to learn how to use lm317 and don’t forget to share it might help someone.

I hope you can now build a 5-volt power supply easily by yourself comment if you have any problem.

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