Running Lights by LM555 + 4017

Advertisements

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 going one full circle the the first LED lights again and it goes on. You can vary the value of R2 100K Linear potentiometer to make LEDs run fast or slow. The frequency of oscillation of astable 555 is given as f = 1.44 / ((R4 + 2 * (R2 + R3)) * C3)
The 10 outputs have 10 green LEDs. The current thru the LED is limited by R1, the current can be calculated like this (9V - 1.6V) / 1K = 7.4mA this is within 20mA which is the danger limit of the CMOS output. You want it to be bright use transistors for every output.

Buy light running circuit

The cap C1 is a filter and C2 is to prevent noise at pin 5 influencing the output as it is a control voltage point.
You can cascade or chain many more counters with the CO or carry out pin 12 of 4017. The pin 15 reset is kept at low for counting, on high it will reset the counter but is not used in this circuit.

Source:
http://www.electronics-circuits.com/schematics/catDigital_Circuits.html

400Watt power inverter Variable power supply Wireless alarm systems
Power Supply   Switching Power Supply   DC to DC Converter   Inverter
Battery charger   Led flasher   Motor speed controller   LM317   IC 741
RF radiofrequency   Electronic control   Digital Circuit   Alarm home system
DC to DC converter step up voltage   Mini project   Temperature control
FM receiver   Dual power supply   Fluorescent lamp   Pic microcontroller
Led display   RF amplifier   FM transmitter   LM324   LM723   TL494
2N3055   LM338   SG3525   Li-ion battery charger   Pulse generator