This circuit controls the channel separation as described in the March 1973 Radio Electronis magazine article. The circuit was proposed by Mullard (Philips) and consists of two channels as shown.
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...