I have some questions about how it is possible to dim an LED using PWM. I saw some videos and explanations of how the duty cycle affects the brightness and some methods to effectively dim a LED with different components, but I´m missing some detail here.
What can be summed up is that for a duty cycle of n% the brightness of the LED will be n% of what it would be with the 100% duty cycle and this is explained with the average values and total energy in time that is being provided.
If we had two cases, one simple signal-resistor-LED circuit with 50% duty cycle and one with 20% duty cycle (the only thing that varies is the duty cycle,) and we could inspect an instant of time in the positive cycle for each case we should get the same values of voltage and current since we aren't using energy storage devices. It is also said that the brightness of the LED depends on the amount of current provided, hence we should get the same brightness during the positive cycle even if one lasts longer than the other. If it is receiving the same current, where does the dimming happens? If the answer is in the way our vision works, does that mean a specialized tool would perceive the same brightness?