Christmas LED lights circuit with 555 timer

  
This circuit sequence through a pattern of Christmas lights to turn on and off each string of lights, one at a time. After sequencing through all strings, the circuit turns the last string off, then turns all strings on, and then off, before repeating the pattern. Some simple wiring changes will let you set up other patterns. This circuit provides for five strings of lights, but you can increase or decrease the number, and adjust the timing.
Christmas LED lights circuit with 555 timer - schematic

A 555 timer chip supplies about a 0.5 Hz signal to an SN74LS93 4-bit binary counter chip that counts between 0002 and 1112. (The circuit uses only the 74LS93's 3-bit counter.) The counter's outputs connect to an SN74LS42 decade decoder. PART LISTS RESISTORS R1 6.8k VR1 100K R3, R4 220 Ohm ICs IC1 Timer 555IC IC2 1 to 10 Decoder 7493 IC IC3 1 to 16 decoder 7441 IC (N1,N2) IC4 IC 7400 – NAND Gate DIODES D1 – D16 LEDs OTHERS C1 Capacitor 5μ 25 V C2 Capacitor 0.01μ BATT Battery 5 Volt




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