DC current regulator

Discussion in 'The Projects Forum' started by Skittles, Aug 27, 2012.

  1. Skittles

    Thread Starter New Member

    Aug 17, 2012
    1
    0
    I am looking for a DC circuit that outputs a constant current level even if the load resistance changes. The power source would be a 9v battery.
     
  2. KJ6EAD

    Senior Member

    Apr 30, 2011
    1,425
    363
    LM134 and similar will provide up to 10mA. Just Google "current regulator" or "constant current source" for others.
     
  3. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    7,386
    1,605
    How much current? How accurate? Is there a cost constraint? Size constraint?
     
  4. wayneh

    Expert

    Sep 9, 2010
    12,087
    3,027
    A traditional approach is to have an op-amp watch the voltage across a low-ohms shunt resistor, and compare it to a reference voltage. The voltage is proportional to current flowing through the shunt (and your load). The op-amp then controls the voltage on the base of a transistor, which in turn regulates current to the load. The current is adjustable by changing the reference voltage.
     
Loading...