This 1967 Motorola circuit is intended for operation with signals up to 250 MHz delivering a 50 MHz signal at the output. The transistor is the MM1941, uncommon today.
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....