Linear temperature-to-frequency


Posted on Jun 16, 2012

This circuit provides a linear increase of frequency of 10 Hz/°C over 0-100 °C and can thus be used with logic systems, including microprocessors. Temperature probes Ql Vbe changes 2 mV/°C. This transistor is incorporated in a constant current source circuit. Thus, a current proportional to temperature will be available to charge Cl. The circuit is powered via the temperature stable reference voltage supplied by the 741


Linear temperature-to-frequency
Click here to download the full size of the above Circuit.

Comparator ICl is used as a Schmitt trigger whose output is used to discharge Cl via Dl. To calibrate the circuit Ql is immersed in boiling distilled water and PR1 adjusted to give 1 kHz output. The prototype was found to be accurate to within 0 °C.




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

Power-on reset
Driving a buzzer
How the capacitor works (in a debouncing circuit)
Infrared detector circuit using PID20
Toyota MR2 Power Steering System
Simulator Test Tools Speed Circuit Design
Crosswalk Pedestrian Signal and Homemade Controller



Top