Decade Counter IC SN74LS92N
The 7492 is a four-bit ripple counter that has a divide-by-2 section and a divided-by-6 section.
Design of Divide-by-N Counters
A counter can also be used as a frequency divider.
Each flip-flop will divide its input signal by 2 such that the output of the last stage will be a frequency equal
to the input frequency divided by the Modulus number.
A counter with any Modulus number can be formed by using an external gate to reset the counter at a predetermined number.
The logic gate is used to decode the binary equivalent of the MOD number. For a MOD-5 counter, the NAND gate must decode
The decoder can be used to preset some of the flip-flops as well as reset the flip-flops. This means that the count sequence
will start at some state other then zero.
An enable gate (2-input AND gate) can be used to stop a counter when its final state is reached.
System Design Applications
The IC counters can be cascaded together to get larger MOD numbers.
Any special state of a counter can be decoded to light an LED, sound a buzzer, operate a relay or any other external function.
Several 7490s can be cascaded together to form BCD counters.