Re: For those who believe in electricity

On Mon, 7 Apr 2025 15:16:06 -0700, sms <scharf.steven@geemail.com>
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.

It never goes below 0V like AC.

Not going below 0V is the most common way PWM is used.  However, it's
not mandatory or the only way:
<https://en.wikipedia.org/wiki/Pulse-width_modulation>
Note that the waveform shown goes below 0V.

"Sine Pulse Width Modulator (SPWM)"
<https://www.bldcmotor.org/how-to-control-bldc-motor-using-pwm.html>

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.

--
Jeff Liebermann                 jeffl@cruzio.com
PO Box 272      http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann      AE6KS    831-336-2558