Normaly closed IRF510

Discussion in 'General Electronics Chat' started by mazur50, Jul 6, 2011.

  1. mazur50

    Thread Starter Member

    Feb 5, 2007
    I have a IRF510 that i need to be normal closed and when pulled to ground it opens up.

    I have it setup right now with a 50ohm resistor to the high side but when it is pulled to ground the resistor gets hot which makes sense because it is shorting.

    is there a way i can drive this with a transistor

    I need to switch the switch the low side and it needs to be normally close and open when ground is applied.

    Any help would be great.

  2. iONic

    AAC Fanatic!

    Nov 16, 2007
    Perhaps you only need a Power Transistor. What is the application? Can you include a circuit diagram?
  3. SgtWookie


    Jul 17, 2007
    What is the "high side" voltage relative to the MOSFETs' source terminal?

    Try replacing the gate pull-up resistor with one of a much larger value, say 3.3k. It won't turn on really quickly, but when you short the gate to the source using your switch, it will turn off very quickly - and the resistor won't get hot.