This repellent operates with frequencies from 30 to 45 kHz, serving for insects and rodents. The circuit is from 80s documentation. The transducer is a piezoelectric type.
This simple metal finder uses a 100 uA indicator. The exploration coil must be constructed in a...
This resistance meter has a linear scale, converting resistances to voltage. The operational...
This circuit was found in a 1995 documentation. Its purpose is to indicate voltage levels that are...