Simple Variable power supply circuit 0-30V 2A

If you are beginners who want to use the simple variable power supply 0-30V 2A. This circuit is best for you. Because it has a few parts, small, and cheapest than others circuit that same power. The features of this handset are the DC voltage continuously from 0-30 volts and apply current up to 2 amperes and can put easily in a large pro box.

How it works
Figure 1 is a circuit diagram. We apply AC line to the circuit to SW1 on/off to the transformer T1 and fuse F1 to protection circuit when too much power source.

 

Beginning Variable power supply circuit 0-30v 2A
Figure 1 Beginning Variable power supply circuit 0-30v 2A

T1 reduce AC voltage 220V into 24V 0 24V. Then, the current through to both diode D1, D2 to rectifiers to DC voltage. Next, C1 filter current to DC voltage about 36V.

There are LED1 to show power on and R1 limit current to a safe value.

R2-100ohms and ZD1-30V are connected together as the 30V steady DC regulators.
The variable resistors VR1 is used to adjust the output voltage between 0V to 30V, that have transistors Q1, Q2 increase the output current up to 2A. Also, there is the short-Circuit protection include Q3, R3.

How to builds
The circuit assembly is very simple Because the devices are less Can assemble down on the perforated board. While the power transistor Q3 – 2N3055 is working, will hot so we always use a heat sink on it.

Should use low wattage soldering iron does not exceed 30 watts. The soldering the legs of transistors and diodes we should use the pliers with leg devices Because these devices cannot be very hot.

Adjustment and usage
The prototype works well, have ripple voltage at output lower than 1 mV and the output voltage will drop lower than 0.1 volts


In real usage that although it off, LED power ON will still light up for a moment. Because the LED gets current from C1 that does not discharge fully.

If you want to stop LED immediately. You may move R1 and LED1 to across the secondary of T1. Then, add the diode-1N4001 series with LED to protects voltage backward which LED may be damaged as Figure 2

The LED will outage immediately when switched off
Figure 2: The LED will outage immediately when switched off

 

If need to use the dual power supply (Positive Ground and Negative terminal) For testing amplifier OCL.

We change the rectifier section to new, from a Full-wave into the bridge and use the two secondary coil; 24V 2A. Then, apply the negative and positive of each channel to the ground as Figure 3

Making supply is 2 sets with bridge diode and capacitor
Figure 3: Making supply is 2 sets with bridge diode and capacitor

 

The parts you need

Q2, Q3: 2N3055 Power NPN transistor
Q1: BC548,BC549, 45V 100mA NPN Transistor
D1, D2: 1N5402 3A 100V Diode
D3: 1N4002 1A 100V Diode
ZD1: 30V 1W Zener
VR1: 10K Potentiometer
R1: 3.3K, 0.25W resistor
R2: 100 ohms, 0.5W resistor
R3: 0.3 ohms 10W resistor.

Be careful Components pinouts

Some parts on this have different pins. You need to put it in the correct way only!

Be careful component pinouts on power supply circuit
Be careful component pinouts on power supply circuit

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Salim khan

Thanks.

chayapon

Hi, Salim Khan
Thanks for your feedback.
You are welcome.

Augusto Principato

Very interesting !

walter

simply—–the best!

chayapon

Hi, Augusto Principato
Thanks for your feedback.

chayapon

Hi, walter
Thanks for your feedback.

Subodh

where is the placement of VR1 10k pot. I can not see it in figure

chayapon

Hi, subodh
Thanks for your feedback.
Please look at the figure 1.
VR1-10K ,

Lily

hi is this still uselful with 12 0 12 volts transformer?? can u make using 12 0 12 volt transformer.?

spewkz

hi, how can i change the output to 3 Amp in this schematic diagram?

Efraem Salcedo

This circuit is great. It works. Thanks!

Aravind

Hey! Plz explain me! How the current is amplified … Coz , its confusing me! Make it fast, or reply to my mail id. [email protected]

Mamdouh

Hiii
I would like to send me some mini circuits

Jed Frances Ararao

a current limit function would be very nice..anyone can tell me how to add a current limiter function to this circuit?

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