This sequential tone generator circuit was found in the July 1980 issue of Radio Electronics magazine. It uses well-known integrated circuits. The tones are generated by programming resistors.
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...