A thermistor should do the job. You can buy them in SMD packages and down to 0.1% accuracy. How much resolution you get depends on the measurement range and the ADC you are using.
A platinum RTD would be another candidate but requires more signal conditioning. In 3-wire or 4-wire probe configuration you can compensate for long probe wires. Any sensor you choose should have a thermal mass less that the item you want to measure. Generally, a smaller sensor means smaller thermal mass. If you really need to resolve 0.01ºC or 0.001ºC then you also need to pay attention to: * sensor self-heating * consider turning off excitation between measurements * with a thermistor, go with a high R25, i.e. 100kΩ which will help with keeping self-heating low. * Temperature coefficient and environment of the thermistor's series resistor. * Stability of the supply/reference voltage. BTW, 0.1% resistors are sensitive to static discharge. A zap can easily produce a 0.5% change! Having really good and stable thermal contact is essential. The item you are measuring and the sensor should be in an isolated micro environment. Airflow or proximity to anything of a different temperature will potentially cause a temperature gradient between sensor and the measured item. All passive temperature sensors require some sort of linearization, but that could be done away from the sensor or during post-processing. For thermistors search for the "Steinhart Hart equation". I am not aware of active (smart) sensors with have better than 0.1ºC resolution, but I also have not done any significant search lately. Cheers -- Manfred VK3AES On Sat, Sep 26, 2020 at 12:46 PM Hal Murray <[email protected]> wrote: > > > I've got a collection of 1-wire gizmos and USB thumb drives. They are great > for many applications but I'm looking for something better/different. > > I'd like something that reads to 0.01 degree or 0.001 degree. I don't need > accuracy. What I want is reasonable linearity so I can make pretty graphs. > > I'd like the actual probe to be small enough so I can poke it inside gear like > a PC and attach it to a crystal. > > I'm looking for a USB or serial connection so I can log the data. > > Is there an obvious brand/whatever I should be looking at? thermistor? > thermocouple? ... > > I don't care about a display on the device. I don't want a logger, they fill > up. I want to grab the data on the fly and do my own logging. (But I'm happy > to use a logger if it will do what I want.) > > > -- > These are my opinions. I hate spam. > > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. -- Manfred VK3AES _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
