This nonlinear gain circuit was found in a 1965 Electronic Design. The configuration can be used as a basis for modern designs with equivalent transistors.
This fast trigger circuit allows the counting of up to 300 pulses per minute. The circuit is from...
This intercom uses transistors from the 60s. It was found in a Japanese publication at the time....
This circuit is from an old publication from the 90s, but it can be adapted to operate with LEDs....