Experiment 5 - The Mod-10 Counter

A special place among counters has the mod -10 counter. The mod -10 counter passes through 10 states before he starts anew and thus it is interesting when the decimal number system is used...

In a mod-10 counter you are using a 4-bit counter that actually has 8 states. However, when the counter reaches the seventh state (Q3 = 1, Q2 = 0, Q1 = 1, Q0 = 0), you force the counter again to return to the state (Q3 = 0, Q2 = 0, Q1 = 0, Q0 = 0)...

For this you use an AND gate, whose output is connected with the RESET inputs of the flip-flops...

Circuit diagram mod-10 counter.

Illustration states of the Mod-10 binary counter.

With the circuit shown you realize easily that the counter now produces only 10 states...

Circuit mod-10 counter. (Enlarge)

You find a mod-10 counter in many applications which counts in the decimal numeral system.

Now there are also counters that count down...