Bench POWER Supply (circuit)

Introduction: Bench POWER Supply (circuit)

About: Hi! I make different things :)

Hi! Let's make a bench power supply. This is the first part about electric circuit. The next time I will show you how I've made a wooden case.

Step 1: Parts

I used:

1) Power cable -

2) Power socket -

2.a) Fuses -

3) AC to DC power Converter (24v) -

4) Voltage and current regulator (1.3 - 24v) -

5) Precision Potentiometers 10 kOhm -

6) Potentiometer Knobs -

7) Voltage and Amperage Monitor (10A) -

8) Banana Socket -

8.a) Banana Connector -

9) mini DC Power Converter for fan -

10) Temperature Controller -

11) Fan (40mm, 12V) -

Step 2: AC 110/220V Input

The Power Socket has a 10 amperes fuse.

It means if we connect any electrical appliance, which consumes more than 10 amperes, the fuse will be blown and protect our circuit (blowing and short circuit protection test in the video).

Step 3: AC to DC Power Converter

The main part of our project is this AC to DC power Converter.

Input: AC from 85 to 265V.

Output: DC 24V.

Maximum load is about 4 Amp. It gives us 24 * 4 ≈ 100W

The Power Converter has an overload protection and short circuit protection (test in the video).

Step 4: Voltage and Current Regulator

Input: DC from 7 to 32V.

Output: DC from 1.3 to 28V.

Maximum Output current is about 8 Amp.

Let's replace small potentiometers with large Precision Potentiometers.

Step 5: Precision Potentiometers

I used these Precision Potentiometers (R=10 kOhm). It is more accurate then single-turn potentiometers.

Pin layout:

- old Potentiometers: 1-2-3

- new Potentiometers: 2-1-3.

Be careful and solder, as in the picture.

Step 6: Voltage and Amperage Monitor

There are several models of voltage and current monitors. I advise you to buy with 4 numbers, because monitors with 3 numbers have less accuracy. Also use a 10A monitor for this project, because the 50A monitors do not work with low current.

Working voltage: DC4V-28V

Measuring Range: DC 0-200V, 0-10A.

(watch checking in the video)

Step 7: Cooler

Now, if we want to use our bench power supply in a case, or for a long time, or use it at full capacity, we need to add a cooler.

The type of cooler depends on the case. But now I'm going to use only this 40mm fan. This is a 12V fan. So, we need to use a mini DC power converter to get 12V from 24V. There is a voltage regulator.

The last part for today is a Temperature Controller. It has a temperature sensor, indicator and relay.

You can configure at what temperature the fan will turn on and at what temperature it will turn off. Depends on you case.

Just connect all modules like in the picture.

The hottest point of my circuit is AC-DC Converter's radiator. I put the temperature sensor into it. I'm gonna glue it using Thermal Compound Paste in the future.

Step 8: Сonclusion

So, today we've made our own 120W Bench Power Supply.

This is "easy to repeat" project. So, if you want to do something like this, please, ask your questions in the comments, I'll help you.

And watch the video, there are several tests.

Thank you, bye!

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    4 Discussions


    1 year ago on Introduction

    The thin black wire in the VA meter is connected internally to the thick black wire and it will short out the current shunt in the current limiting DC-DC converter so the current limit pot will not work properly. Also the current reading will be wrong. I think you need to disconnect the thin black wire, then everything will be OK. Then you can power the VA meter from 24V (thin red wire to 24V, yellow/white to +ve terminal, thin black not connected.


    Reply 1 year ago

    Thank you! I really didn't think about it. But I've tested this ammeter display in this circuit using my multimeter and it shows true amperage. However, I should check amperage protection. Maybe my DC-DC module doesn't have shunt inside?


    Reply 1 year ago

    Hi, your meter is connected to the adjustable output so it will be OK, but if the voltage goes below 4V it will go off and the LEDs won't show voltage or current. If you connect the thin red wire to the 24V supply then you will need to disconnect the thin black wire. Then the LEDs will always be on, even for 1V output.


    Question 1 year ago

    Hi... Every one
    I want to make a rectifier regulator, required 2v voltage and 15 amp current to my bike for another use plz help me give your valuable suggestions....plz