This circuit was obtained from the April 1978 Radio Electronics magazine. The other circuit is a PLL of the time. The power supply must be 15 V symmetrical.
This sequential circuit of LEDs was found in a Popular Electronics from the 90s. The circuit can be...
Indicated for 12 V systems, this circuit was obtained in a 90s Siliconix documentation. The...
This circuit for light modulated in frequency (FM) operating at 50 kHz was found in a 90’s...