Shift register fundamentals: A shift register moves the _____ left or right. With serial loading, a word is stored by entering _____ bit per clock pulse; with parallel (broadside) loading, it takes one _____ pulse to load the word.

Introduction / Context:
Shift registers are sequential logic circuits that move stored data left or right on each clock edge. They are used for serialization/deserialization, time delays, and simple state manipulation. Understanding serial versus parallel loading is key to using them effectively in digital designs.

Given Data / Assumptions:

• A shift register stores a multi-bit word.
• Serial loading feeds bits one at a time on successive clocks.
• Parallel (broadside) loading writes all bits simultaneously on a single clock.

Concept / Approach:
On each active clock edge, a shift register transfers each flip-flop’s state to its neighbor, effectively moving bits left or right depending on wiring. Serial input streams in 1 bit per clock into the end cell; parallel load uses a dedicated load signal to capture an entire word at once with one clock event.

Step-by-Step Solution:
Identify what moves: data bits shift left or right per clock.Serial load: add one new bit each clock until the word is fully captured.Parallel load: assert load; on the next clock, all bits latch simultaneously.Thus fill the blanks: bits, one, clock.

Verification / Alternative check:
Datasheets for universal shift registers (e.g., 74HC194/195) describe both serial inputs (SER) and a parallel load (PL) controlled by a single clock edge, confirming the terminology.

Why Other Options Are Wrong:
“light” and “right” are incorrect nouns for what is shifted. “Register” is not the timebase; loading is synchronized by a clock.

Common Pitfalls:
Confusing direction labels (left/right) with MSB/LSB placement; mixing up the separate load enable versus the clock signal.

Final Answer:
bits, one, clock