This circuit was found in an 80's Poptronics. The circuit is a fast trigger whose signal can be taken from the Q2 collector. The supply can be done with voltages from 9 to 12 V.
Used with telephones at the time, this circuit was found in Popular Electronics from the 90s. The...
Found in a 1965 CQ magazine, this circuit uses period components. The unijunction transistor can...
This dimmer configuration is quite old, as it was found in a 1967 publication. The triac can be of...