Variable Bench Power Supply With Active Cooling

Introduction: Variable Bench Power Supply With Active Cooling

About: I like finding new uses for things, making things, and improving things. I'm a student who is currently looking for a better job, one where I can make an actual difference.

I needed a new bench power supply that would be variable and inexpensive. I decided to reuse an old laptop power adapter that was not being used anymore and it gave me a nice filtered 19 volts DC. I then made up the circuit for the LM350 Variable voltage regulator on a breadboard to make sure it worked. The circuit for the LM350 is really simple, uses few components and is readily available online. After doing some testing I realized that when you draw more than 1.5 amps of current the LM350 runs hot, it is rated for 3 amps with a large Heat Sink. To help the Heat Sink  I decided to have a small 12 volt  2" fan automatically come on when it detects significant heat on the heat sink. To Do this I used the LM311 automatic fan control that uses a thermistor to sense temperature, the circuit for this is also readily available online and its really simple to make. To power this circuit, the fan and the voltmeter I used a LM7812 which is a really simple 12 volt regulator. I would have liked to used a Trim pot with a knob on the front but I did not already have one that was the right value. Other than that everything worked out great and I was able to reuse things that I already had.

Green Electronics Challenge

Participated in the
Green Electronics Challenge

Sensors Contest

Participated in the
Sensors Contest

Gadget Hacking and Accessories Contest

Participated in the
Gadget Hacking and Accessories Contest

Be the First to Share

    Recommendations

    • The 1000th Contest

      The 1000th Contest
    • Battery Powered Contest

      Battery Powered Contest
    • Hand Tools Only Challenge

      Hand Tools Only Challenge

    2 Discussions

    0
    Hassanul_
    Hassanul_

    6 years ago

    Do you have a circuit schematic/diagram?

    0
    Khaleel123
    Khaleel123

    Reply 6 years ago on Introduction

    The Circuit Schematics are available online for each IC used. LM350, LM311, and the LM7812. I didn't include them because they are really easy to find, with a quick google search.