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Hi Brad,
Take heed, I can only vouch for the -002 version; that's the one with the metal body, although I suspect the -007 and -016 are similar.
>So are you saying it switches internally to 2.7v regardless of whether I apply 4, 5, or 12 volts to that input pin?
Well, not exactly. I'm saying it functions to heat the wire with the same effect whether you put 4V, 5V , 12V or even about 2.7V on it. I mean the burn off pin is just the input to a switch, not something with a linear function. If you're going to use battery voltage to trigger the burn-off, I suggest using a 33K ohm resistor in series with the 12V source. While providing ample current to turn the burn-off switch on, it would prevent heat from being dissipated by the 1K film resistor on the ceramic substrate that is in series with the input pin.
>I need to supply 12v to the meter IN ADDITION to some non-critical voltage to the burn-off circuit.
You are right. The AMM needs to be powered for the burn-off to occur. The burn-off pin doesn't provide this power.
When I test the burn-off function there is no air flow. The wire is heated to a red-yellow and the AMM signal output (function of the wire voltage) is about 4.2V. I have no idea if this voltage is fixed or would be increased if there was an air flow cooling the wire, like it would be in normal operation. I suppose it would be easy enuf to check...
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Art Benstein near Baltimore
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