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 drain dip oscillator was found in an old English documentation. The JFET can be of any type...
This SCS counter circuit was found in a 1964 General Electric documentation. The circuit has a...
This is the circuit of a commercial radio from the 60s, sold in Japan. The circuit shows the...