thermistors in parallel

John Larkin · 2023-05-06T02:10:22+00:00

Imagine a chassis with up to eight plugin boards. The chassis has apair of PWM controlled fans. board will have a thermistor to sense board temperature. If anyboard thinks it's too hot, it asks the fan controller to jog the fanspeeds up a notch. If nobody requests more air, the controller jogsthem down. That will work.But I have a board with eight channels that can each get hot. There'sno place on the board that represents the worst-channel temperature. Ionly have two available ADC channels so I can't use eight thermistors.But thermistors are radically nonlinear. If I parallel fourthermistors into each ADC channel, the hottest of the four willdominate. That should work well enough.Some sort of diode thing might select the hottest thermistor, butparalleling is easy.Or add a secondary ADC mux, I guess.

May 06, 2023 Last reply: 3 years ago 41 Replies

Rate this thread:

John Larkin 3 years ago

Yes, great inside control loops. Cheap too.

Vote

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required