This circuit is from the 80's but uses common components today. The relay is voltage sensitive according to the power supply used. Transistors may be general purpose types.
Using three gates of t4011 this oscillator produces a rectangular signal with frequency given by...
Found in a 90s Popular Electronics, it serves both TTL and CMOS logic. The injector can provide 10...
This circuit, with the TBA810 circuit, which is no longer common today, was found in a 1985...