The figure shows how to implement an alarm buzzer in an LM3914 to warn about crossing the scale limit. The circuit can use other types of warning.
This circuit uses a CA3140, an operational amplifier with FETs in the input stages. Equivalent can be...
Found in a Popular Electronics from the 90s, this circuit has a configuration that has been widely...
This circuit was found in an American 80s circuit manual. The components used are unusual. The...