I have an idea for a project, which needs to be able to measure temperatures up to 260°C. The accuracy is not crucial (±5°C is fine) but it is important that it can measure lower temperatures too.
I initially thought of using a silicon diode such as the 1N4148 as forward voltage is proportional to temperature with a nice linear slope of -2.1mV/°C. The current will be <100µA.
However, it looks like these diodes cannot survive a temperature this high, although it is not specified exactly what failure might occur. Can I expect the silicon die to break down and not work properly at this temperature, even though the current is low? The environment will be 260°C for 3-10 minutes, so it looks like any soldering rating is irrelevant.
If this does not work, what other low cost options are there for measuring high temperatures?
Best Answer
Forget the diode - for this temperature you would need either a thermocouple or an RTD.
You can get either type suitable for what you want to do for a few pounds, check on places like Farnell, Mouser, etc under temperature sensors.