Detecting high voltage

[mivanov]

I am pretty new to electronics, trying to figure out the best and safest way to use a high-voltage signal from one device to briefly turn on another 5V circuit. The high-voltage device is an invisible dog fence collar, and I would like to be able to detect whether the collar got activated. It's almost the inverse of a relay, if there is such a thing. I am guessing the high voltage pulses on and off very quickly, but I guess the first step would be to measure exactly what it looks like. Any ideas?

This is my first post so please let me know if this isn't the right place, etc. Cheers!

 

[BobK]

Put a low current (1ma?) fast acting fuse across it.

Bob

 

[CocaCola]

Most of the fence collars I have seen have either a tone or LED indicator when they trigger, you could count off that low level signal... Also the circuit inside is low voltage, you can tap the low voltage trigger signal before the amplification and output stage...

 

[mivanov]

Love the quick responses! I like the fuse suggestion but let's say I don't want to have to replace a fuse every time. I may be able to get inside and tap into the pre-amplified curcuit, that sounds like it would be the best solution assuming it's accessible. Any other head-on solutions?

 

[BobK]

My suggestion was somewhat tongue-in-cheek, as it MIGHT have been a solution, depending on how you intended to use it. But if you are happy trying to tap inside, I agree with CC that that would be a good solution.

Bob

 

[mivanov]

I do appreciate that Bob, the simplest solution is often the best. I am happy to tap inside but not sure if that's an option yet. But if I had to use the high voltage leads, any idea where to start?

 

[CocaCola]

IMO trying to count the high voltage is going to be nothing short of an unreliable nightmare... You could try a voltage divider and try to temper it down to something you can work with, but I personally wouldn't bother when you can almost certainly tap into the low voltage side and be up and running reliably in no time...