# Adjustable Dummy Load Circuit Diagrams

Adjustable Dummy Load Circuit Diagrams
This dummy load can be very helpful in testing power supplies, storage batteries, and similar devices. It has a variable load resistance and enough current handling capacity.
Ordinary dummy loads are usually made of fixed value resistors. They are cheap, readily available, and easy to assemble.
But for power dissipations above 10 watts, it is quite difficult to find the appropriate resistors. Their load resistance value is also fixed.
One excellent solution to this problem is using a dynamic dummy load. This dummy load not only can dissipate high power levels, but its load resistance can also be varied.

Adjustable Dummy Load Circuit Diagrams |

### Adjustable Dummy Load Circuit

This dummy load can be very helpful in testing power supplies, storage batteries, and similar devices. It has a variable load resistance and enough current handling capacity.

Ordinary dummy loads are usually made of fixed value resistors. They are cheap, readily available, and easy to assemble.

But for power dissipations above 10 watts, it is quite difficult to find the appropriate resistors. Their load resistance value is also fixed.

One excellent solution to this problem is using a dynamic dummy load. This dummy load not only can dissipate high power levels, but its load resistance can also be varied.

The circuit featured here uses a 2N3055 transistor with an emitter resistance of 1 ohm per 5 watts. It functions as a variable current sink.

The current flowing through the transistor can be varied by applying a voltage at its base.

The load current value (IL) can be found with the ff: formula:

IL = (UV=UBE)/ R

Where

UV = base control voltage

UBE = base-emitter voltage

R = resistance at the emitter

The 2N3055 transistor must be heatsinked. The heatsink helps the transistor handle loads up to 45 watts.