74191 IC Up/Down Binary Counter

The 74LS191 is a binary down and up counter uses the clock pin to be able to increase or decrease the output binary, it also has 4 inputs to give parallel to the output of the integrated circuit, the configuration of parallel or series can be controlled . 

74LS191 Binary Counter Details

Synchronous up and down BCD decade counter 74LS191.

A counter is a sequential circuit built from flip- flops and logic gates capable of storing and counting the impulses (often related to a clock signal), which it receives at the input intended for this purpose, and also acts as a frequency divider. Typically, the computation is done in binary code , which will frequently be the natural binary or the natural BCD (decade counter).

A counter is a circuit in which its outputs follow a fixed sequence that starts again when it ends, or circuits that receive their data serially ordered at different time intervals. Input pulses can be clock pulses or originate from an external source and can occur at fixed or random time intervals. The number of outputs limits the maximum number that can be counted.