Tunnel diode simple noise generator (CB23705E)

This circuit was found in Radio Electronics magazine from November 1960. The circuit is powered by a photocell of the time.

Unijunction Delayed Switch (CB15036E)
This circuit causes the load to switch on only after a time given by R1 and C1. The SCR must be...
Sequential 100 LEDs (CB17483E)
This circuit causes the LEDs of an array of 100 LEDs to flash sequentially along the lines. The...
24V x TTL Interface (CB24898E)
The figure shows how to interface a 24 V signal with TTL logic using a 4N26 coupler. The circuit is...