This circuit was found in 1980s American documentation. The transducer is a piezoelectric capsule and the power supply voltage can be between 3 and 18 V.
This circuit was found in a 1963 magazine, but can still be easily assembled with some current...
This loop antenna was found in a 1990s documentation. The circuit includes a field strength meter. The...
This sensor uses a capacitive system that oscillates at 45 MHz with the empty glass tube. Its...