This circuit was found in a Popular Electronics from the 90's. The output signal can be applied to a headphone or speaker. The microphone can be a piezoelectric tweeter capsule or other type.
This circuit we have a practical idea to improve the performance of voltage regulators. The idea...
The BFO or Beat Frequency Oscillator is used to receive telegraphic signals or even modulated in...
Found in a1968’s Burr Brown documentation, this shield uses an integrated circuit from that time,...