Builtin multiturn potentiometer enables precise frequency control. L version frequency range: 0.8 Hz to 60 Hz. Output is a square wave signal delivered at the output terminal. Amplitude is approximately equal to the input voltage, allowing straightforward interfacing with standard logic inputs and measurement equipment. Duty cycle is not adjustable. The output duty cycle remains stable during frequency adjustments, typically in the 50% to 65% range. Benefits and performance: simple, reliable signal source with no external components required for frequency setting; wide frequency range within the L version supports a variety of timing and testing needs; amplitude compatibility with common input signals facilitates easy integration into existing test setups. Use scenarios: 1) Clock or timing signal source for microcontroller and digital circuit testing, enabling verification of timing behavior at different frequencies. 2) Bench testing and calibration of measurement equipment (oscilloscopes, data acquisition systems) with a repeatable square wave reference. 3) Educational experiments and signal integrity checks on RC and other frequencydependent circuits, observing responses as frequency varies.