This circuit, with printed circuit board, is from an article in Radio Electronics magazine from May 1971. The circuit uses the C106 which was already a common component at the time.
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...