A Current Regulator

Thread Starter


Joined Aug 26, 2011
Hello! I am working on a project that is very heat sensitive, and requires a current to be regulated to a specific amount in various places. I do not want to use a resistor as they release heat. I was looking towards another approach. Would it be possible that if I attach a 20mA 10 volt diode, that it could regulate such a current as long as the load doesn't take more than 20mA at 10 volts?
I have an image attached that shows what I plan to do.
So the 100mA diode will regulate 100mA to the 20mA diode and transistor,
the 20mA diode will regulate 20mA to the base of the transistor, which turns it on
and the motor gets 100mA 10 volts.



Joined Jul 17, 2007
Any linear current/voltage regulation solution will result in the consumption of power, and it will be released as heat.

If you wish to reduce the radiation of heat to a minimum, you will need to go to a switching regulator solution. If you wish to avoid the use of resistors altogether, you will need to use a Hall-effect sensor to detect the current flow.

Potato Pudding

Joined Jun 11, 2010
Your diagram shows a connection for motor as a load and your battery and circuitry tell me that would be a DC motor.

For a DC motor you really would want to use a Pulse Width Modulated Motor Control.

It would be the most efficient method which means the least waste heat.

It will also extend the battery life.

PWM controllers can provide a much more accurate and powerful motor response.

A resistive or linear motor control is not anywheres near as good - and would only (barely) be suitable for an extremely simple and low power application.

Edit: Switching regulators use PWM. The Motor Controller is a regulator for motor speed and may include current sensing (good to protect against motor stall overloads) or abstract to only current sensing. Often a motor regulator has a sense for rotation speed.
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