7 Segment LED Counter

Schematic

7 Segment Display Reference

Parts

Part Total Qty. Description Substitutions R1-R7 7 470 Ohm 1/4 Watt Resistor U1 1 74LS90 TTL BCD Counter IC 7490,74HC90 U2 1 74LS47 TTL Seven Segment Display Driver IC 7447,74HC47 DISP1 1 Common Anode 7 Segment LED Display MISC 1 Board, Sockets For ICs, Wire

Notes

1. All pulses to be counted are to be TTL compatible. They should not exeed 5V and not fall below ground.
2. You can add more digits by building a second (or third, or fourth, etc...) circuit and connecting the pin 11-6 junction of the 74LS90 and 74LS47 to pin 14 of the 74LS90 in the other circuit. You can keep expanding this way to as many digits as you want.