This circuit was found in a Popular Electronics of the 1990s. The sensor is a rotating mechanical system with a propeller-driven magnet to count pulses with a reedswitch.
This circuit for discharging NiCad batteries limits the current to a value that can be adjusted in the...
We found this regenerative receiver with JFET in a documentation from the 1980s. L1 has a primary of...
Found in a 90s Electronic Design, this circuit can be used as a shield in current projects. The...