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



At 3:30 PM -0300 5/5/10, CARABAJAL PEREZ, MARCIAL ROBERTO wrote:
The point of the project is to experience firsthand the copper temperature coefficient value, the difficulties to use it for such purpose, and the suitability of more specific devices such as thermistors. The idea is to use cheap operational amplifiers, or 2-3 transistors, diodes and resistors, and battery.
The indicator can be any analog or digital tester, or even a few leds.
One team should make this with the original copper coil, another team with carbon resistors, and another team should make similar but with a thermistor. After that, they can develop conclusions.


Do you have a source for the carbon composition resistors?
They haven't been manufactured in that form since the '70's.
Low Temperature labs around the world kept the production line running a bit longer with their promises to buy up a stockpile of these jewels.