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A simple gauss detection switch?

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wsemajb

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I've been approaching this from many angles and contacted dozens of people. I'm going crazy. I'm getting bloodied. I can't believe it's this difficult.

I'm going to back up to the very beginning and just pose it as a simple query. Maybe I'll get lucky.

Is there an ultra sensitive gauss meter circuit/schematic anywhere that constitutes a simple indicator? No measurement. No scaling. No accuracy. Just hall device/ic on a board with power supply inputs, a bit of signal conditioning of maybe a dozen more parts, and a little relay.

Tiny bit of gauss detected, little buzzer or light goes off. That's it. That's all!

Anything?
 
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How much is "a tiny bit of Gauss"?

I'm assuming you've run into the things on this page before:
You mean something like this? They're used in geartooth detectors and other such devices but all seem to need the magnet to be real close.
https://www.lessemf.com/dcgauss.html
If you look at the linear hall effect sensor it has an output of 1.3mV per Gauss. That might be the limitation of hall effect sensors in general which might be where all your problems are coming from.

It's got me wondering why you never see hall effect sensors in things like compasses. You always see some kind of magneto-resistive or magneto-inductive sensor for those kinds of things, but those are neither straightforward to work with, nor easily available.
 
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Hi dknguyen,

These are diagrams from the page you linked.
**broken link removed**
**broken link removed**
Is it possible to implement so simple a circuit? Or are these merely rough application examples? Sensitivity would only depend on the IC that is inserted, no?
I've got a few of these I've been experimenting with....
https://www.electro-tech-online.com/custompdfs/2010/06/eq-711l_gmw.pdf

I'm trying to find a circuit that I can use to detect current flowing through a conductor.
About five amps in an 18ga conductor. Very low gauss.

Here's another circuit from last year in this forum....
**broken link removed**

And another that I've come across earlier...
https://i802.photobucket.com/albums/yy303/svejkovat/SDC11293.jpg

I'm in the process of testing that last one and it may work for me. But I've asked a few questions about it here and elsewhere and don't seem to be making any headway.
The simpler the better. I just want an ultra sensitive switch circuit. I'm experimenting with placement of the sensor chip in various ferrite rings for better sensitivity. Here's one example...
https://i802.photobucket.com/albums/yy303/svejkovat/SDC11104.jpg
It's an 8mm ID split ferrite snap-on choke with a hall sensor cemented into the gap.

I need to know when any current, as low as five to ten amps, is flowing through this conductor
**broken link removed**
It's 8mm in diameter. Water cooled interior. Copper stranded conductor.
All I want to do is detect the current in order to operate a relay. I don't wish to measure it.
 
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Maybe these?
**broken link removed**

Yeah, you could always increase the sensitivity by wrapping the cable in a coil and maybe even some kind of core and sticking the sensor in the middle...you know...like an electromagnet. With that reasoning you could probably make it arbitrarily sensitive or use an arbitrarily insentive detector. I didn't realize your application had a wire with current that could be coiled. I thought it was some kind of hand meter or something. THat makes things a lot easier.

You haven't said what difficulties you were running into earlier. Seems to me that the coiling to increase the magnetic field for the same level fo current would overcome any problem with the sensitivity. Is the current DC or AC? AC would require a more complicated circuit (or a latching magnetic switch) since the field alternatives from + through zero to -.
 
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Whether it is one way or the other will only the condition that causes on or off in the presence of current.
 
Whether it is one way or the other will only the condition that causes on or off in the presence of current.

I have used these little units with good success as to a yes/no current indication.

For measuring AC current presence you really don't need much. The item I linked to is little more than a coil of wire driving a small rectifier with a LED out there. Since you just want a yes/no you really don't need much.

Ron
 
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