Wednesday, November 13, 2013

Zero 2 Nine counter

This is a sequential circuit design, Mod10 means it will count from 0-9. This would be probably your first long circuit, but don’t worry because you have a breadboard arrangement ;)
555 timer is in astable mode and it will produce a clock pulse, which is controlled by 100k potentiometer.
This clock pulse is input to 74LS90 which is a decade 0-9 ripple counter. Kindly use the 74LS90 if some one tell you that you can alternatively use 74LS93.. so let me tell you though they have same pin configuration and work same but the thing is 74LS93 is 0-15 ripple counter, so you will face some garbage outputs after counting up 0-9 which you don’t want. I tried my best to use 74LS93 and use reset pins to make it Mod 10
well, 74LS90 is a BCD counter but as we are showing a display on 7 segment so we need a driver IC
74LS90 is cascaded to 74LS47 which is a BCD to 7-segment display driver
and at last the seven outputs of 74LS47 are connected to 7 segment display.
Parts Required:
  1. 100k(potentiometer), 47k & 1k
  2. 0.1mF & 2.2mF
  3. 555 Timer
  4. 74LS90
  5. 74LS47
  6. 7 Segment Display Common Anode
  7. 9V battery with clip
Circuit Diagram:
Bread board Arrangement:
Pin Confiiguration:

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