Any way to lower current w/o affecting resistance?

Discussion in 'General Electronics Chat' started by CableGuy84, Aug 9, 2011.

  1. CableGuy84

    Thread Starter New Member

    Aug 9, 2011
    *I did search and couldnt find much.*

    I have a curcuit that is controllable by a pot (potentiometer).

    It is approx .6V and at max resistance via the pot the current is ~40mA, and low resistance is ~140mA.

    I want to try to use a digital Pot but most DigiPots I find are a max of 1mA continous and/or 20mA switching.

    Is there ANY way to lower the amperage of this curcuit... even lowering it before the DigiPot and then raising it back after? I'm willing to spend 20-30 dollars if possible and can wire it up if I had a basic understanding of how it worked.

    Thanks for your help


    Thanks for any help.
  2. praondevou

    AAC Fanatic!

    Jul 9, 2011
    Please post your circuit diagram.
  3. bertus


    Apr 5, 2008

    You can have the digital pot to create an adjustable voltage.
    A voltage to current converter can make the current wanted of it.

    As already asked, post your actual schematic.

  4. CableGuy84

    Thread Starter New Member

    Aug 9, 2011
    Sorry guys - I dont have a circuit diagram of the item that needs the resistance, it is a mass produced item and in a case so I have no idea on the circuitry inside.

    I just took some measurements last night of the curcuit (with the manual POT) at the different resistance levels.

    Sorry I can't provide more info. I am not very knowledgable in this dept which is why I came here.

    Just a note... the only curcuit I am talking about it the circuit with the Pot on it.
    Last edited: Aug 9, 2011
  5. CableGuy84

    Thread Starter New Member

    Aug 9, 2011
    Also, just to be sure that I am reading my multimeter correctly:

    On the 200m setting on my multimeter, I connected it in line and it reads 143 (which is where I got the ~140 from).

    Is that 143 milliamps = 143mA correct?
  6. SgtWookie


    Jul 17, 2007
    Yes, that is 143mA.

    Besides the pot, what are you using to supply the voltage; what is your source of power? Voltage and rated current is what I'm looking for. If the voltage is low, your options are going to be very limited.
  7. CableGuy84

    Thread Starter New Member

    Aug 9, 2011

    This is a LED driver that uses a manual pot. It has a total of 6 wires. It has a 120v in (2 wires), and then something like 20V out (2 wires) @ 700mA and then a third set of wires that goes to the POT - a wiper and the B side of the Pot.

    That is it. The voltage of the pot circuit is .6v and ranging from 40-140mA depending on the resistance set by the Pot.

    Thx for your help thus far wookie.
    Last edited: Aug 9, 2011