Hi
I'm trying to detect 240v 50hz without direct contact. The circuit needs to be quite reliable, and very selective (ie only pick up one cable from a bundle).
I have developed the following circuit which simulates OK in ltspice, but I would really welcome comments / suggestions before I order the bits and build it. I don't have access to a scope so fault finding once I've built it is tricky!
The idea is to wrap a piece of thin single strand wire (like a cat5 core) about 5 or 6 times around the cable I'm trying to monitor, which I figure should induce some sort of 50hz signal in it, then send that through a 50hz band-pass filter (IC1) with quite high gain, followed by a comparator (IC2) with a preset to set the reference voltage to give some sensitivity adjustment. Then a quite crude diode/cap to flatten it out and a buffer (IC3) to drive the output. The zener probably isn't necessary but it gives a nice steady flat output regardless of current, and allows me to drive the next stage which will be an AND gate to combine several of these circuits.
I'm only using the 1013 op-amp because I know where I can buy them and ltspice has a model for it!
improvements
==========
I'd love to loose the 3rd op-amp as the 1013 is a dual package and that would mean only one IC. Is this even the best way to do it? If anyone has a different idea I'd love to hear it.
I would really appreciate any help/suggestions/ideas/insults!!
Thanks.
I'm trying to detect 240v 50hz without direct contact. The circuit needs to be quite reliable, and very selective (ie only pick up one cable from a bundle).
I have developed the following circuit which simulates OK in ltspice, but I would really welcome comments / suggestions before I order the bits and build it. I don't have access to a scope so fault finding once I've built it is tricky!
The idea is to wrap a piece of thin single strand wire (like a cat5 core) about 5 or 6 times around the cable I'm trying to monitor, which I figure should induce some sort of 50hz signal in it, then send that through a 50hz band-pass filter (IC1) with quite high gain, followed by a comparator (IC2) with a preset to set the reference voltage to give some sensitivity adjustment. Then a quite crude diode/cap to flatten it out and a buffer (IC3) to drive the output. The zener probably isn't necessary but it gives a nice steady flat output regardless of current, and allows me to drive the next stage which will be an AND gate to combine several of these circuits.
I'm only using the 1013 op-amp because I know where I can buy them and ltspice has a model for it!
improvements
==========
I'd love to loose the 3rd op-amp as the 1013 is a dual package and that would mean only one IC. Is this even the best way to do it? If anyone has a different idea I'd love to hear it.
I would really appreciate any help/suggestions/ideas/insults!!
Thanks.
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