non-inductive resistor

Discussion in 'General Electronics Chat' started by nin, Sep 9, 2010.

  1. nin

    Thread Starter New Member

    Sep 3, 2010
    Hi all, I am looking for resistor which have low inductivity. I came across wirewound resistor type which is non-inductive styles, but I have to order and it takes about four weeks to reach here (I'm in the UK, and the product is in US).

    Anybody can suggest any 100Ω 25W resistors with low inductivity and can withstand high temperature. The resistor is actually the load, for the circuit that consist of IGBTs.

    Or if anybody can suggest other types of load that have low inductance, I would be very happy.

    Thank you.
  2. Wendy


    Mar 24, 2008
    Get the highest wattage carbon resistors you can, and parallel accordingly. You didn't mention tolerance, so you have an opportunity to make it tighter with judicious test selection.

    Allow a small air gap between the resistors. Not much, but enough for air to flow between them
    Last edited: Sep 9, 2010
  3. timrobbins

    Active Member

    Aug 29, 2009
    I agree with Bill. You can use a ground plane (pcb) to solder the ends of all the parallel resistors, and make a wide short connection to the circuit - keep everything short and tight and close and you have a great low inductance resistive loop. You can contemplate small 2W (eg. PRO2 resistors) then.
  4. marshallf3

    Well-Known Member

    Jul 26, 2010
    Carbon resistors would not be my first choice, they tend to change value over time when used in power circuits. This was however more related to the brand, if you can find good resistors made by Ohmite or Allen-Bradley you should be good.

    Dig about the various surplus sources, you might get lucky especially if you can find some old mil-spec components.

    I know for a fact that the U.S. doesn't have a monopoly on wholesale parts suppliers, even some of the larger ones have branches across the world so keep looking on that too.

    A non-inductive wirewound is going to be your best choice but they don't exhibit perfectly non-inductive characteristics, they're usually made by winding them such that the inductances of more than one layer cancel each other out.
  5. Wendy


    Mar 24, 2008
    Actually the older carbon resistors had that problem, but the newer dumbbell shaped ones are very stable. You don't find the perfect cylinder types anymore, it is one of the ways you can tell.
  6. bertus


    Apr 5, 2008
  7. bountyhunter

    Well-Known Member

    Sep 7, 2009
    We always used 3W metal -oxide resistors in our snubbers which had to be ultra low inductance.