Hello, I was wondering what the difference between PWM and Frequency was and found this online.
Is this correct?
"Frequency is how often a signal switch between low voltage and high voltage. Frequency is expressed in cycles per second, or Hz.
Duty cycle is percent of time that the signal stays at high level. It is typically expressed as the percentage of the period.
PWM is a combination of frequency and duty cycle
As an example, a 100MHz signal (100 million cycles per second) has a period of 10ns. If the signal has 5ns high and 5ns low period, the duty cycle of this signal is 50%. However, if the high signal is 3ns and low signal is 7ns, the duty cycle would be 30%."
Sounds right to me.
I've never heard of anyone using PWM at 100MHz though...
[u]Arduino PWM[/u].
PWM operates at a fixed amplitude (voltage) for the high part of the cycle, and it usually operates at a fixed frequency but it may have a variable duty cycle.
It makes an LED appear dim (at 10% PWM it's off 90% of the time, etc.) because it's too fast for our eyes to see it blinking (with the default Arduino PWM) frequency.
I makes a motor run slowly because there is less energy and the inertia of the motor prevents it from starting & stopping that fast. An incandescent light bulb will be truly dim for the same reason. The heat in the filament can't change that fast.
Frequency -
…For sound, the "traditional" hearing range (for a young person with normal hearing) is 20Hz to 20kHz. (Sound is analog so there is no PWM. There is only frequency and amplitude.)
Low frequencies are bass and high frequencies are treble. All real-world sound is multiple-simultaneous frequencies. We perceive pitch (related to the musical note) as the lowest or most dominate frequency. A guitar and trumpet can play the same note but they sound different because of the harmonics & overtones.
A loudspeaker vibrates back-and-forth. At 1000Hz, the speaker makes 1000 full back-and-forth cycles every second. i.e. At higher frequencies it moves faster.
The amplitude (or amount) of movement determines the loudness.
PWM is a combination of frequency and duty cycle
No that is wrong.
A PWM signal has a frequency and a duty cycle. it is not a combination, it is a property of a PWM signal.
It is like saying that a car is a combination of transport and colour. A car is a transport and it has a colour.