Simple Current limiter circuit? 30a-50a....

Thread Starter


Joined Feb 1, 2019
Is it feasible to build a relatively simple circuit to limit current to around 30 to 50 amps? Doesn't not need to be very accurate.

But without lowering the voltage more then 0.5v or so?

The voltage of the circuit would always be between 12v-13.8v


Joined Mar 14, 2008
Do mean the voltage shouldn't drop more than 0.5V when the current is below the limit point?
As LQC noted, you can't limit the current without reducing the voltage.
And limiting the current can dissipate a large amount of power, equal to the voltage drop across the limiter times the limit current.


Joined Jun 30, 2021
There are plenty of ways to do that as long as what crutschow and LQC stated is true. That is you want the voltage drop below 0.5V when the current is less than the limit. What is the application?


Joined Aug 21, 2008
My reading of it is that the thread starter does not want the voltage burden of the current sensor to be more than 0.5 volts.

For AC circuits there are current transformers that can be used to detect currents like and and not drop much voltage. Certainly voltages below 0.5V should be easily attained.

For DC circuits Hall effect current sensors can fill you need.

Have you considered using a circuit breaker?


Joined Jan 23, 2018
If the goalis protection, there have been published circuits for the "electronic fuse" for many years. The devices do not attempt to regulate the current, but rather to switch off if a limit is exceeded. That does make much more sense, and is certainly much more efficient, and effective.
But we do need to have a clarification as to what the TS actually wants.