Linear active test load

128

01:20:51

This circuit is good for testing a power circuit with. It allows one to draw a specific current from it. It acts as a current limiter. The resistor towards the ground is to linearize the temperature dependency of the darlington beta value. Otherwise the current will rise as the temperature rises in a runaway effect until burnout.

If this circuit can be actively controlled by a microcontroller, then this resistor can be much lower, but can never be removed.

With current settings the load is sinking about 600W of power. About 2W is burned in the resistor. 

published 6 years ago

hurz

6 years ago

Must be a big transistor/heatsink, not very common. What is this circuit for, burning power?

niko_20010

6 years ago

It is a so-called "electronic load" or "dummy load"

niko_20010

6 years ago

Usually even 200W loads have 6+++ BIG (!) transistors -- think TO-3

hurz

6 years ago

ok, i have one, 10A max 60V but max 150Watt with a single mosfet in TO247. TO3 case is a little old

hurz

6 years ago

And for useability its not a common collector its made as common source!

niko_20010

6 years ago

Mine is 200W and has 6 TO-3 monsters in it (one of the bigger brothers of the 2n3055 is used there)

niko_20010

6 years ago

200W, 40V, 40A

niko_20010

6 years ago

beautiful fully analog device

hurz

6 years ago

40V*40A is 1600Watt it must be also limited to 200Watt. 6 2N3055 suppose todo more then 200Watt, but it needs a proper heatsink as well

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