Circuit diagrams and schematics - Electronic projects

This simple circuit functions as a 12 LED chaser. A single illuminated LED ‘walks’ left and right in a repeating sequence, similar to the effect seen on KITT, the car in the Knight Rider TV series. Fully commented source code and programmer ready HEX files are provided for the PIC 16F84A and 16F628A at the [...]

This neat little circuit provides 8 LEDs directly driven from the PIC along with a single mode control switch. The firmware elsewhere on this page drives the LEDs with a 5 bit PWM signal providing each of the 8 LED channels with four levels of intensity; off, dim, mid, bright. A number of sequences are [...]

The 555 Astable generates a clock for this circuit, an oscillator giving a square wave output at pin 3 which is counted by 4017 to give a running lights effect. The decade counter-divider CD4017 has 10 outputs, for every low to high transition at the clock input, rising edge, the counter advances one LED. After [...]