This ultrasonic digital remote-control transmitter was found in the January 1976 issue of Radio Electronics magazine. The components are from the period. The IC is from the period.
The figure shows how to implement an alarm buzzer in an LM3914 to warn about crossing the scale...
This circuit can act as a shield being controlled by a microcontroller by pin 1 or 2. The...
This circuit was obtained from a 1980's QST magazine. The circuit can generate 1 to 15 MHz signals...