Re: For those who believe in electricity

On 4/7/2025 6:16 PM, sms wrote:

On 4/7/2025 9:28 AM, Zen Cycle wrote:
 <snip>
 

"PWM DC"? PWM by definition isn't DC. PWM generators even at maximum drive aren't 100% duty cycle (yes, effectively DC considering the response of the LED, but still not exactly DC).

 Yes. PWM is a DC voltage with varying pulse widths.

nope, As soon as you start introducing 'pulse widths' you're no longer talking about DC.

It never goes below 0V like AC.

I see, you're using AC in the context that "alternating current" reverses current flow with respect to ground (certainly a valid interpretation).
The more generic usage of 'AC' is a sinusoidal waveform, which may be sitting on a bias that prevents it from going above or below the ground reference.
That said, I'd be interested to see a reference claiming a PWM waveform is DC. I couldn't find one. It's pulsatile, which by definition is not considered DC.

 BTW, Frank could have just used a transformer like <https:// www.amazon.com/dp/B094NRRKC1> to simulate a 6VAC dynamo, or even a 16-24VAC doorbell transformer with some resistors to divide the voltage and limit the current, but it's really not worth spending much money to try to fix an inexpensive bicycle headlight.

but hey, he's retired, he doesn't have much else to do besides bitch about helmets in a usenet group.