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Variable Power Supply: Everything You Need to Know

Have you been asking what a variable power supply is? Here we got the answer for you. Therefore, in this article, we will help you know what a variable power supply is. Additionally, we shall highlight some of the best variable supply devices. Finally, read this piece till the end.

1.What is the Variable Power Supply?

Switching power supply

A variable power supply is a controller that electricians use to test the voltage capacity in a project. Additionally, a variable power supply has a range of applications. Therefore, you can use the power supply as a gauge to ensure the project can endure a given amount of current load and voltage. 

2. How to Build a Variable Power Supply?

Step 1: collecting the components

Parts List:

  • LTC3780 DC Adjustable Converter
LTC3780 DC Adjustable Converter
  • Digital Voltmeter Ammeter Display
Digital Voltmeter Ammeter Display
  • 12V DC Fan
12V DC Fan
  • 7805 IC For 5V
  • 12V 3A Adapter
12V 3A Adapter
  • 100uF & 10uF Capacitor
  • 1N4001/1N4007 Rectifier Diode
  • Banana Socket 4ps
  • Knob 2ps
  • DC Switch
  • 2.1mm DC Jack Connect
  • Wires
  • Heat Sink
  • Wooden Blocks
  • PCB Board
  • 4mm Acrylic Sheet

Tools List:

  • Glue Gun
  • SuperGlue
  • Sandpaper
  • Mini Hand Saw
  • Soldering Iron
· Soldering Iron
  • Masking Tape
  • Drill Machine
  • Rotary Tool
  • Spray paint

Step 2: Cutting the Acrylic Sheet

Acrylic sheet

Acrylic sheet

Acrylic sheet is the best material to make the enclosure of the power supply. Measure the material and cut it according to the marking. Then, follow the following guidelines:

  • Place the voltmeter display and mark it.
  • Next cut the marked section with a rotary tool and metal file.
  • Again, mark the areas for air passing
  • Cut the marked area using a mini hacksaw.
  • Take the measurements of the socket, the switch, and the fan, then mark it.
  • Drill the holes and smooth the edges with a metal file.

Step 3: Sanding the Pieces

First, get off the paper cover of the sheet. Then, finally, sand the acrylic sheets until the flat surface becomes smooth.

Step 4: Attaching the Pieces

First, apply super glue on the edges of both sides of the panels. Then, join the side of the panels to one another.

Step 5: Painting the Pieces

Paint the lower and upper enclosure of the power supply using a black color or any color of your choice.

Step 6: Attach Extra Pieces

Take four pieces of the same size for mounting the screws. Finally, join them using super glue.

Step 7: Attaching Front and Back Panel

First, apply enough super glue on the ends of the front panel. Secondly, immediately place it in the lower enclosure and hold it for some minutes. Finally, use the same procedure to fix the back panel.

Step 8: Mounting Components

First, mount the switch, then using a screw, mount the fan. Finally, mount the remaining components.

Step 9: Mounting the Heat Sink

To reduce the temperature of your power supply, a heatsink and a cooling fan are essential. Follow the steps below:

  • First drill holes on the wooden block
  • Use the screw to attach the heatsink to the wooden block.
  • Now apply hot glue to the wooden block.
  • Attach the wooden block to the enclosure.

Step 10: Wiring Diagram

Connect every component to another according to the circuit plan.

Step 11: Final Assembly

Finally, attach the upper enclosure with screws. Then, you are good to go, and the power supply is ready for test and usage.

3. How to Select a Variable Power Supply?

Linear output regulation

Switching variable power supplies are smaller than linear unstable power supplies. Additionally, switching supplies offer additional control capabilities, but linear supplies are a better option for benchtop power supply. Moreover, power density is not a problem on the bench, and switching supplies have higher output noise specifications than linear supplies.

Multiple outputs

If you need to use your DC power supply on multiple applications, you require more than one output. Moreover, with this, you can connect many supplies to a circuit under test. Therefore, when going for a supply with many outputs, choose one with separate outputs since you can operate each separately. 

Control flexibility

Having separate controls for voltage and current is a must-have on a variable power supply. Additionally, the voltage control should be an independent fine-tune control or a multi-turn control. Moreover, the controls should allow you to set the output voltage as you wish.

Output enable/disable

This feature allows you to turn the output on and off without switching the supply entirely off. Additionally, you can set up the supply fear of how the adjustments may affect the load.

PC control functions

In almost every application, PC control is necessary. It helps to automate most of the repetitive tests you carry in your project. Moreover, doing this in your project will improve its productivity.

Tekpower DC Variable Power Supply

DC power supply on a white background

DC power supply on a white background 

Tekpower DC power supply is one of the best variable Power Supply. It comes with a current range of up to 30V and a voltage of up to 5A. Additionally, its set up and read back resolution has a voltage of 0.01V and a current of 0.001A.

Moreover, another essential feature of Tekpower variable DC power supply is a transformer-based linear power supply.


  • Firstly, it has an OCP and temperature sensor based cooling fan
  • Secondly, it comes with a line and load regulator
  • Additionally, it does not produce much noise
  • Moreover, it has an adjustable voltage and current
  • Finally, it is pocket friendly

KORAD linear-digital Variable power supply

A digital power supply

A digital power supply 

The KORAD is an adjustable linear variable power supply with an adjustable voltage output of 30V and 5A. Additionally, as in any bench power supply, it supports constant voltage and constant current modes and comes with a temperature-controlled cooling fan. Therefore, this linear power supply has overvoltage and short circuit protection.


  • Firstly, it comes with a long power cord.
  • Secondly, it has a high input voltage of 220V 50Hz
  • Additionally, it comes with a USB connection
  • Moreover, it comes with a 2-year warranty
  • Finally, it is less costly

Eventek Digital Switching Variable Power Supply

A digital switching power supply

A digital switching power supply

Eventek digital DC switching variable power supply is an affordable power supply. In addition, it comes with an adjustable output voltage of up to 30V and an output current of up to 5A. Moreover, this is a switching power supply with an efficiency of about 90%.

This product supports both CV and CC mode and automatically switches from one method to another. 


  • Firstly, it is an affordable power supply
  • Secondly, it comes with a long power cord
  • Additionally, it is a lightweight product
  • Moreover, it is the best for schools and training institutes
  • Lastly, it comes with a 1-year warranty

Kungber SPS305 DC Power Supply Variable

Bench power supply

Bench power supply

Kungber SPS305 DC Power Supply Variable is the most reliable and affordable DC power supply. Additionally, the Kungber DC power supply variable is a switching power supply with an adjustable output voltage of up to 30V and up to 5A output current. Moreover, it has other voltage and current variations such as 120V/3A, 60V/5A, and 30V/10A.

Furthermore, this variable power supply comes with four dials for current and voltage adjusting with separate knobs. Finally, like any bench power supply, it supports both CV and CC mode.


  • Firstly, it comes with USB interfaces
  • Secondly, it produces less noise
  • Additionally, it is an adjustable power supply
  • Finally, it is the best for price

Yescom USA DC Variable Power Supply

Adjustable DC power supply

Adjustable DC power supply 

The Yescom USA DC power supply is an Adjustable DC Power Supply. it is a reliable power supply with an output voltage of up to 30V and an output current of up to 10A. Moreover, it comes with over-voltage, over-temperature, and current protection features.

The front panel of the Yescom DC power supply has a three-digit voltmeter and ammeter. Additionally, it has four knobs for fine, coarse adjustment of voltage and current.


  • Firstly, it has output ripple and noise reduction
  • Secondly, it comes multiple protection for extended usage
  • Additionally, it has a long power cord
  • Finally, it is pocket-friendly 


Since the variable power supply is essential equipment for most projects, I believe this guide is a great help. Additionally, you can choose one of the best variable power supply according to your power requirements.  Nevertheless, go through the user manual before using your DC power supply. Finally, feel free to share the same with your friends.

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Emma Lu
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