Main chip: NE555; Input voltage: 5V15V DC Key benefits Simple, reliable timing solution: NE555 based pulse generator for versatile waveform generation without microcontrollers. Clear output monitoring: an LED indicator shows the output state at a glance. LED on at the low level, LED off at the level, and the LED blinks when the frequency is relatively low, enabling easy oscilloscopeless verification. Wide, flexible frequency control: selectable frequency ranges provide broad coverage with fine adjustment within each range for smooth, continuous tuning. Adjustable duty cycle: the duty cycle can be finetuned, offering control over pulse width. Note that the duty cycle and frequency are not independently adjustable; changing the duty cycle will alter the frequency. Specifications Main chip: NE555 Input voltage: 5V15V DC Output indication: LED shows state as follows: LED on during low level, LED off during level; LED blinks at very low frequencies Output frequency range (selectable for continuous adjustment) Low frequency range: 1 Hz to 50 Hz Medium frequency range: 50 Hz to 1 kHz Medium frequency range: 1 kHz to 10 kHz frequency range: 10 kHz to 200 kHz Duty cycle: tunable; note that duty cycle and frequency are not independently adjustable. Adjusting the duty cycle will change the frequency. Use scenarios Scenario 1: Signal generation for bench testing and oscilloscope demonstrations. Use the selectable ranges to produce clocklike pulses or slow square waves for alignment and measurement tasks. Scenario 2: Timing or trigger source for microcontroller projects and digital logic experiments. Use the LED indicator to quickly verify output activity without additional equipment. Scenario 3: Prototyping and lab experiments requiring adjustable timing signals. The user can finetune both duty cycle and frequency within the available ranges to explore timing behavior and response in circuits.