This self-heated constant-temperature-delta transistor anemometer is cheap, rugged, and sensitive. It relies on the relationship between airspeed (AF) and thermal impedance (ZT = o C/W) of a heated ...

This project is a simple and effective Rain Alarm System built using a Darlington Transistor Pair for signal amplification. The system detects water droplets (rain) and triggers a buzzer or LED alert.

A recent Design Idea presents a circuit to measure an airflow rate up to 2000 fpm using two transistors in a Darlington configuration. One transistor works as a self-heated thermal sensor and the ...