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Re: [Phys-l] Cheap Classroom projec to sense water temperature



I take it the bolometers** I made by coating thin PC board w/ carbondag are similar to the glass coated carbon film resistors. If not, then that's a possibility.



** 2nd sound

bc has boxes of 1/4 to 2 W carbon composition resistors from the forties, fifties, and sixties. This makes him an Antique?


p.s. A possibly interesting thermal sensor is a globar from a toaster oven. I think they are SiC and a "type" of thermistor. I'm collecting them to make a furnace.

On 2010, May 05, , at 14:03, John Denker wrote:


As CB hinted, the temperature coefficient of modern
thin-film resistors is not interesting. Antique
carbon-composition resistors are much more interesting
... probably too interesting, because there is no
simple theory to explain what happens