Finally got to take a look at a thermocouple gas valve -- I've always
maintained they were impossible, and I was right!

First of all, I had the impression that they would open the valve (which I
flat wouldn't believe) but in fact they only hold it open after you pusha
da but.

This one came from a water heater, RobertShaw control.  There's a sheet
metal U with *six* turns of looks like #20 enamel on each vertical
leg.  The valve stem has a washer on the end that completes the magnetic
circuit.

Takes about 125 ma to hold the valve open, which the thermocouple supplies
at just about 2.5 millivolts giving 0.3 milliwatts.  Full hot the t/c puts
about 7 mv into that circuit >> ~350 ma. and 2 milliwatts.

Load resistance appears to be 0.020 ohms.

Talk about doing the mostest with the leastest!

david
David Beierl - Providence, RI
'84 Westy "Dutiful Passage"
'85 GL "Poor Relation"