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Re: [Phys-l] CFLs again



For a digital wattmeter that displays V, I, f, P, E, PF, and more for
any plug-in 120V appliance see the "Kill-A-Watt" by P3 International.
Perhaps the best price is at:

<http://www.supermediastore.com/kilwateldet1.html?WT.mc_id=AdWordsKillaWattkillawatt&WT.srch=1&gclid=CL-1-fmtn4wCFQGPWAodwm8k5w>

Bob Sciamanda
Physics, Edinboro Univ of PA (Emeritus)
www.winbeam.com/~trebor
trebor@winbeam.com

----- Original Message -----
From: "Bernard Cleyet" <bernardcleyet@redshift.com>
To: "Forum for Physics Educators" <phys-l@carnot.physics.buffalo.edu>
Sent: Friday, May 18, 2007 2:46 PM
Subject: Re: [Phys-l] CFLs again


| Since the CFLs use a transformer, (and possible a capacitor input)
the
| i-V phase may not be zero (impedance not pure R) and therefore, i*V
may
| not = W.
|
| That's why I asked. The old d-Arsonval watt meters automatically
| corrected for this by using the i to power (w/ a shunt) the
| electro-magnet and the V w/ a multiplier the moving coil. To check
this
| use a double beam or dual channel CRO. One channel; reads the i
using a
| small value resistor in series and the other the V across the lamp.
Are
| they in phase? One may thereby measure the angle and correct the
i*V value.
|
| bc, owner of two d-Arsonval watt meters.
|
| Spagna Jr., George wrote:
|
| >Bernard asks:
| >
| >
| >
| >>-----Original Message-----
| >>From: phys-l-bounces@carnot.physics.buffalo.edu
| >>
| >>
| >[mailto:phys-l->bounces@carnot.physics.buffalo.edu] On Behalf Of
Bernard
| >Cleyet
| >
| >
| >
| >>bc wishes to know the method GSJ used to measure power.
| >>
| >>
| >
| >Students put an ammeter in series with the lamp, and voltmeter in
| >parallel. Both were digital multimeters reading true RMS current
and
| >voltage. P = IV
| >
| >
| >
| cut
| _______________________________________________
| Forum for Physics Educators
| Phys-l@carnot.physics.buffalo.edu
| https://carnot.physics.buffalo.edu/mailman/listinfo/phys-l
|
|
|
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