This is the circuit diagram of a very simple up down counter that can be used of a large number of applications. The circuit is based on the IC CD40110BE which is a CMOS decade up/down counter. For ICs are used here. Common cathode seven segment display is connected to the 7-segment output of each IC.Display connected to the IC1 represents the lowest number and display connected to IC4 represents the largest number. Synchronous counting is achieved by connecting BORROW and CARRY pins of the preceding stage IC to the CLK DOWN and CLK UP of the next stage IC. For UP counting trigger pulse must be given to the pin7 of IC1 and for down counting trigger pulse must be given to the pin9 of IC1.The RESET pins of all IC are shorted and they have to be connected to ground during normal operation. Connecting the RESET pins to positive supply using the switch S1 resets the counter.
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