This circuit causes an LED to flash at a frequency determined by the capacitor. The circuit is powered by only 3 V and can be used for signaling.
We found this MW radio in a 1957 Raytheon publication. The transistors can be modern equivalent types...
This circuit has no lock, but it has a very low consumption feature in the standby condition. We...
This circuit is from a Popular Electronics from the 90s. It uses an opto-coupler with SCR directly...