This is the receiver for the previous transmitter. The microphone is of the high impedance ultrasonic type. The circuit activates a relay. The operational amplifier supports equivalent.
This preamplifier appears elsewhere in this section and this version was found in American...
This 2000 circuit, found in the documentation of the time, is intended for charging this type of...
Based on the well-known LM3909, this LED pulser circuit was found in American documentation from...