We found this circuit in a 1964 Electronic Design. It provides 0.5 V signals from 4 kHz subcarriers. Transistors are from the era.
This circuit causes an LED to flash at a frequency determined by capacitor C1. The circuit can be...
This flasher or neon signal powered by batteries was found in old documentation. The transformer must...
This circuit was obtained from an ancient American documentation, but appears elsewhere in this...