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 circuit generates pulses at a frequency that can be adjusted by a potentiometer. The circuit is...
This oscillator uses a small IF transformer taken from an old transistor radio. FET admits...
Found in a 1970 EEE, this circuit generates signals that depend on the C1 capacitor. Transistors are...