We found this circuit in documentation from the 90s. The circuit uses components that are still common today, turning off a load after the programmed time. The time is given by the capacitor.
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...