Mod 5 Counter Circuit Diagram. Decade divide by 10 counters such as the ttl 74ls90 have 10 states in its counting sequence making it suitable for human interfacing where a digital display is required. Thus a 2 bit counter is a mod 4 counter.
1 excitation table for jk flip flop. Note that a mod n counter either up or down is a truncated counter as the sequence does not extend for the full binary range. To illustrate here is a diagram showing the circuit in the up counting mode all disabled circuitry shown in grey rather than black.
The 2 bit ripple counter circuit shown has four different states each one corresponding to a count value.
There are several types of counters available like mod 4 counter mod 8 counter mod 16. There are ic counters that can count both up and down. Counter is the widest application of flip flops. Ripple counter which can count up to value n which is not a power of 2 is called divide by n counter.
