Hello,
I'm a new member and a novice at electrical circuits, so please bear with me

I'd like to create a device - a sort of trouble indicator.

I have a 100mA circuit at around 35V. What I would like to make is a device that I can connect to the circuit that will register if the 100mA circuit had opened (and re-established itself). I'd like to use a simple led indicator that will stay on if the device had detected an open. How would I go about this? I know I'll need a 100mA relay, and I can wire the device to show trouble when the 100mA is open, but how do wire to 'retain' the trouble state?

I'm sure a device like this already exists, but I'd like to learn how to create one on my own.

Thanks

 

Try to Google "latching relay circuit"
Diagrams there should help.

 

for this I would use an actual dual-coil latching relay instead of a relay latching circuit.

 

Thank-you both