Which type of circuit is most often used to generate square or rectangular waves?

The type of circuit most often used to generate square or rectangular waves is the multivibrator. A multivibrator circuit is specifically designed to produce a periodic waveform that can be configured to oscillate between two states, typically resulting in square or rectangular wave outputs. This oscillation results from the charging and discharging of capacitors, and the switching action of transistors within the circuit.

Multivibrators come in several forms, including astable, monostable, and bistable configurations, with the astable variant continuously shifting between high and low states to create a square wave. This makes them ideal for clock pulses and timing applications in digital electronics.

While oscillators can also generate square waves, multivibrators are particularly popular for their straightforward design and versatility when a precise rectangular wave is needed for timing mechanisms. Amplifiers and filters, on the other hand, serve different purposes in electronics—amplifiers boost signal strength, while filters modify signal frequencies, neither of which specifically focuses on creating square or rectangular waveforms.