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 has a frequency range of 30 Hz to 100 kHz with an output signal of 1 Vrms. We found...
This circuit is suggested by the Optoelectronics Sourcebook by Texas Instruments when AC signals...
This sequential relay actuation system circuit for traffic lights was found in Electronics Now...