Gee, guys! You're over-thinking this! Two Honeywell thermopiles in series on one pilot.
That should give you 1.5 volts at enough current to run a digital caliper forever - that is, as long as you keep the gas bill paid.
And if you place them right, it's also a dial light...
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I'm talking about the oscillating magnetic field interfering with the caliper electronics while they're in operation. I wouldn't expect a demagnetiser field to cause problems while the instrument isn't in use.
Fair enough. You might consider using the TO-92 version of the LM317 instead of the TO-220 version, because the TO-92 is less than a 1/4 the size of the TO-220.
And like I said further up the thread, even an LM317 is overkill for something as power-frugal as these calipers. A red LED & a 1K resistor should work just as well, plus you get a free power indicator. ;)
That isn't a very sharp break on the "zener" but it could work. :-) ...lew...
I shoulda typed LM317L. I wouldn't even use a circuit board, just stick the LM317L (TO-92) together with two resistors and a small cap and gob it in epoxy or silicone. It'd be about the size of an acorn, just a bulge in the wire. Another possibility would be a precision shunt regulator like LM385-1.2 or ZR431L I like having a regulator near the caliper for definite regulated output voltage of 1.55 volts regardless of supply voltage.
I might even have some ZR431L's in SOT-23 in the goodiebox. That with three SMT resistors and a cap would be about the size of an M&M.
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