Subject: Re: Caveat Emptor?

From: [email-masked] (Harry H Conover)
Date: 12 Apr 1995 12:44:00 GMT

Malcolm Sanders ([email-masked]) wrote:

: If the bulb operates at 120V
: and draws 0.26A, then the power consumption would be 31.2W, would it
: not?

Perhaps not.  You're not taking power factor into account, and with 
the series ballasts that fluorescent bulbs employ, I'd expect that 
the power factor would be considerably less than unity, and lagging.
Actual power (P) should be something like:

                   P = Volts * Amps * Cos(theta)  

where theta is the phase difference in degrees between voltage and current
waveforms, and Cos(theta) is the power factor.

Even so, labeling of the bulb seems a little cryptic.

                                 Harry C.