This circuit delivers at its output a voltage that proportional to the amplitude of the input signal in a range of 36 dB. We found it in an American documentation from 1966.
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...