In this circuit R1 is 56 ohm and R2 is 220 ohm for the 110 V network. SCRs are according to the load. We found it in Philips 1968 documentation.
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...