How to Build a Simple 5V DC Power Supply

https://www.wikihow.it/Costruire-un-Semplice-Alimentatore-da-5V-DC

For an electronics enthusiast, having a 5 volt DC (direct current) power supply available can be very useful.Many operational amplifiers, microcontrollers, and other integrated circuits (ICs) do require a 5-volt power supply (although most can operate in the 3-15 volt range).This article describes how to build a simple 5V DC power supply, capable of providing a current of up to 1.5 Amperes.You will need to solder various components together.

Steps

Download PDF

Think of the other as the ground terminal.It doesn't matter which of the two you selected as the positive terminal, but, from now on, you must remember your choice.
You are connecting the positive terminal to the anode of the diode;current will flow into the diode through this end and only in this direction, to charge the capacitor you will connect later.
Usually this strip is white and shows the identification of the minus sign.This is the negative terminal, which you will need to connect to the ground terminal of the AC adapter.
That is, connect the positive terminal of the capacitor to the cathode of the diode.The diode allows the current from the transformer to charge the capacitor, and prevents the capacitor from discharging through the transformer during the negative cycle.
Connect Pin 1 of the voltage regulation IC to the connection node between the positive terminal of the capacitor and the terminal on the marked end of the diode. Pin 2 is the ground reference, also called the “Common” terminal, and should be connected to the ground terminal of the AC adapter.Pin 3 is the output.The voltage difference between Pin 3 and ground will be 5 volts.

Advertising

Advice

The terminal near the marked strip on the diode body is always the cathode (negative terminal) of the diode.
You can get all the necessary parts from a common electronics distributor, such as Digikey and Mouser.
Add a capacitor between the output and ground to improve transient response.
The TL780-05 5V regulator is capable of delivering 1.5A of current, but if the AC adapter you use cannot do the same, then the output current of your power supply will be limited by the maximum current of your adapter B.C.
Try using a 12 volt or lower AC adapter.Higher voltages will cause the regulator to dissipate more power, causing it to overheat.
Your new regulator will be able to deliver up to 1.5 A of current, at 5 Volts.The integrated circuit for voltage regulation may overheat in case of higher current values;therefore consider adding a heatsink, in the case of high power applications.
Assemble the circuit on a prototyping board, to facilitate construction.
Even higher voltage values will require precautions and the use of a secondary regulator, to lower the voltage to a value that can be managed by the 5V regulator.
To improve the design, add a full-wave rectifier in place of the current design's half-wave rectifier.
This is a very simplified project;you can find improvements in the technical data sheet of the TL780-05 component.

Advertising

Warnings

None of the voltage ratings used in this project are dangerous.The AC adapter is the only element in contact with the mains voltage.If you want to open the plastic casing of the adapter, make sure you have disconnected it from the power supply first.
The 5V regulator can get very hot when asked to deliver a lot of current.Be careful as it may get so hot that it can cause burns.
By letting the 5V regulator get too hot, you could burn it out early.
If you reversely connect an electrolytic capacitor you could cause it to explode.Make sure that the negative terminal of the capacitor (the one tapped with the strip) is always at a lower voltage than the positive terminal, and that the voltage across the capacitor does not exceed the maximum voltage limit of the capacitor itself.

Advertising

Things you will need

A (generic) AC adapter with an output voltage of 8-30V AC and an output current of up to 1.5 amps.
A rectifier diode such as the 1N5392, or an equivalent one with an average reverse current of at least 1.5A, and a reverse voltage of 50V.
An A 100uF, radial-lead electrolytic capacitor, rated for at least 35V.
A TL780-05 5V voltage regulation integrated circuit, or an equivalent one in a TO-220 package (if it says 7805 it will be fine).
A soldering iron and solder (if you're not using a prototyping board).

Licensed under: CC-BY-SA