Explanation: A bistable multivibrator, commonly known as a flip-flop, has two stable states. It changes from one state to the other only when triggered by an input pulse. When an AC signal (or clock pulse train) is applied to its input, a single flip-flop will toggle its output state for every two input pulses. This effectively divides the input frequency by two. Cascading multiple bistable multivibrators allows for division by higher powers of two, forming the fundamental building blocks of digital frequency dividers used in radio equipment for synthesizers and counters. An astable (or free-running) multivibrator continuously oscillates between two unstable states, *generating* a waveform at a specific frequency rather than dividing an input frequency. An OR gate is a basic logic gate that performs a logical OR operation; it does not divide frequency.