Blown Fuse Indicator

Thread Starter


Joined 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



Joined 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.