This circuit can generate signals of different frequencies, switched by a DC voltage. The frequencies are determined by the crystals. The circuit is from a 90s American documentation.
January 2017 - Omron G7L-x relays for PCB mounting can now be purchased from Mouser Electronics. These...
The circuit below is from National Semiconductor's Linear Applications Handbook. Integrated...
This circuit appears elsewhere on this site. This is from an American 80's circuit manual....