This circuit with pressure sensor was obtained from the Encyclopedia of Electronic Circuits volume 5 of 1995. Note the construction of the sensor with rubber and conductors.
Found in a Popular Electronics from the 90s, this circuit uses a double 555 to emit beeps when the...
This circuit was obtained from National Semiconductor documentation from the 1990s. The circuit has a...
This RF monitor or field strength meter can use instruments from 100 uA to 1 mA full scale. The...