This high-precision circuit was found in documentation from the 1990s. The integrated circuit is an LM111 or another in the series. The circuit has TTL output and can function as a shield.
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...