This circuit drives 4 sequences of 5 LEDs that can be of any color. The frequency depends on the characteristics of the photosensor. The circuit is from an 80's documentation.
This interesting control circuit was found in an Electronics Now from 1988. Through it we can...
This circuit causes neon lamps to flash randomly from a low voltage supply (1.5 to 3 V). The...
Any operational amplifier, like the 741, can be used on this oscillator whose frequency depends on R1...