HD74LS91 8-bit Shift Registers
This serial-in, serial-out 8-bit shift register is composed of eight R-S master-slave flip-flops, input gating, and a clock drive. Shingle-rail data and input control are gated through inputs A and B and an internal inverter to form the complementary inputs to the first bit of the shift register. Drive for the internal common clock line is provided by an inverting clock driver. This clock puls inverter/driver causes these circuits to shift information one bit on the positive edge of an input clock pulse.