Re: [Phys-L] Making video content with incandescent light and 100Hz bands pro...

[Bernard Cleyet <bernardcleyet@redshift.com>]

On 2012, May 13, , at 14:12, Aburr@aol.com wrote:

> but you could make 
> a simple 1/2 (or full) wave rectifier with a capacitor and run your $2 
> bulbs on  DC. (watch out, the peak voltage will be higher than the RMS.)
>
> Alex. F. Burr  


Mmmmm what sort of cap.?


Two 60W lamps present an ~ load of ~ one Ampére   The approximate formula for the cap.  is ripple (in V)  = I/2fC  (full wave rectification)   That's Farads!

So if one tolerates 10% ripple that's a C of   ~ 350 microFd.   At 12V no prob. at 120 equivalent even without the PIV! a biggie.   Try an LC filter -- The L another biggie as not to get hot.     And this is US not the 50 Hz in the Commonwealth.


bc  cheated didn't derive -- found on p. 46 in the  "The Art of Electronics"