74LS194 is a 4-bit bidirectional shift register with a maximum clock pulse of 36MHZ.
In digital circuits, a shift register is a flip-flop based device that operates under several identical time pulses, into which data is input in parallel or serial, and then each time pulse is moved one bit to the left or right in turn for output. This shift register is one-dimensional, and in fact there are multidimensional shift registers, that is, the input and output data is itself some column bits. This multidimensional shift register can be realized by connecting several shift registers with the same number of bits in parallel.
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The data in the shift register can be shifted to the right or left bit by bit under the action of the shift pulse, and the data can be input and output in parallel, serial input, serial output, parallel input, serial output, serial input, parallel output, which is very flexible and widely used.