On Fri, 16 Jan 2009 18:29:57 -0500, Wes wrote:

Don Foreman wrote:

Many industrial sensors integrate this function with a circuit that
switches at some level of field intensity, providing a binary or
"on-off" signal. I'm using a linear hall sensor that provides a
voltage proportional to field strength, about 4.25 millivolts per
gauss. It's the HAL400C from Micronas. Current product would be the
HAL401:

http://www.micronas.com/automotive_a...ion/index.html

Why that one? Because I had 4 of them in my junkbox. Allegro also
makes Hall sensors, and Honeywell used to, probably still does. I
like the differential output on the Micronas for rejection of noise. 4
millivolts isn't much signal when 60 Hz is in the passband. You
probably know what happens when the ground comes loose on a microphone
or magnetic phono jack: HUMMMM! I want this sensor to sense magnetic
field but ignore E field. I'll measure that separately.



Sheesh, you have a nice junkbox. I tried newark and digikey and they didn't carry it.

I got it from DigiKey some time ago. It's not a current part, I've
had it awhile. Parts now available from Allegro, Melexis, Honeywell
and others may well be better.