This xenon flasher version for the power grid is from an 80's EDN. The circuit uses a folder and a pulse transformer to trigger the lamp. C1 determines the intensity of the pulses.
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....