Blown Fuse Indicator

Discussion in 'The Projects Forum' started by manofgresley, Sep 4, 2012.

  1. manofgresley

    Thread Starter New Member

    Sep 13, 2010
    Hi all

    I am a newbie to this forum.
    My question is this, I have come across simple 12 & 5 vdc indicators but not any for say 55 VDC or 240 AC can anyone supply me with a decent schematic / drawing for these?

    Many Thanks

  2. wayneh


    Sep 9, 2010
    For DC, I'd stick with the simple LED+resistor approach. It's not very efficient at higher voltages but efficiency is probably not much of a concern for a 5mA indicator.

    For AC, a neon bulb with a current limiting resistor is commonly used.

    In both cases, the bulb+resistor goes around - parallel to - the fuse. No current flows through the bulb until the fuse opens and a voltage appears across it.