# Four Small 5-volts DC Regulator Circuits

When you want to make a small power supply for digital experimentation,  Small 5-volts DC Regulator. Everyone will tell you, the famous 7805  is best.  Because it is easy to find and inexpensive.

But we have many ways to build a small 5-volts DC Regulator circuit. Using transistors are interesting. It will save you money when you have old parts in your store.

## There are 4 circuits of 5V small regulator

See below as follows.

### First# 5 volts Lab Power supply for beginner

If you like to experiment with digital circuits. It requires a stable voltage, 5V Lab power supply. In the hurried time. But cannot buy the integrated circuit.

Let’s use the transistors to build the 5v voltage regulator circuit.

Some friends have the old equipment. You may be able to apply it.
It may power to output up to about 5V 2A.

See in the circuit. This is a simple Zener diode and transistor regulator.  First, T1 transform AC main to lower AC voltage, 6.3V.  Then, come to the unregulated power supply section, D1 to D4, C1. It has DCV at C1 is 8.4V.

Next, this voltage is applied to R1 and ZD1, to keep the stable voltage regulated, 6.2V.  Next, Q1 and Q2 increase higher current to the output. C2 and C3 reduce any noise and any ripple voltage.

Recommended: 7805 regulator datasheet & pinout

Parts list

Q1: BD139, 1.5A 100V NPN transistor
Q2: TIP41, 4A, 40V NPN transistor
R1: 470 ohms 0.5W Resistor tolerance: 5%
R2: 1K 0.5W Resisotor tolerance: 5%
Electrolytic Capacitors
C1: 2,200uF 16V
C2, C3: 100uF 16V
ZD1: 6.2V Zener Diode 0.5W or 1W.
T1: 6.3V or 9V 2A transformer.

You will get the 5V Lab power supply that gives the output current about 2A.

### Second# 5 volts Linear Power Supply Regulator Using 2N3055

This is  5 volts Linear power supply regulator circuit. It uses electronics parts that found easily, no Zener diode, and an integrated circuit.

They use the transistor 2N3055 and others. Which seek easily use diode perform heal voltage be stable. By diode 1N914 number uses 1N4148 number can replace.

If you do not have the transistor-2N3417 you may use BD139 instead. Using the transformer about 1A-2A current, the output current will give about 1A.

### Third—5V/ 0.5A Regulator using 2N3055-TL431

It is an easy linear supply circuit with 2N3055 and IC TL431 — Voltage Reference – Shunt Voltage Reference—. There is very well quality more than  Zener diodes, and also cheap.

### Last: 5 volts regulator using LM309

This circuit use LM309K, old DC regulator IC.  It is convenient for Digital Circuits.  The output voltage is  5V at 2A current.

Get Ebook: Simple Electronics Vol-03

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### 8 thoughts on “Four Small 5-volts DC Regulator Circuits”

1. Good info on simple power supply circuits. The English translation is not very good. need to get better translation software.

• Hi bob,

2. Hi, @bob
I am very happy you like my site.
Yes, I use google translate Thai to English.
Sorry for error.

Thanks.

3. i am bio medical engenereng tecneshan

4. Very pleased to find this site, these circuits.

Thank you for them.

Keep up the good work!

David 🙂

5. Hi, David
Happy new year.

6. i have a question about –> Four Small 5-volts DC Regulator Circuits <–

I’m currently working with a 12v AA batteries for a power supply and i need the output voltage to be
5v 2.5 amps i have seen a lot of step down and buck converters that are 5v 2.5amp, but
for the others that are 5v 3amps or 5v 2amps what would be needed to get Amps to 5v 2.5 amps?