need help

Discussion in 'General Electronics Chat' started by the teacher, Mar 25, 2008.

1. the teacher Thread Starter New Member

Mar 25, 2008
5
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wich one of the following a.c values has the same heating effect as the equivalent d.c value

A. effective value
B. average value
c. peak value
d. peak-to-peak value

2. sudharshan Member

Mar 3, 2008
11
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It is P=VAcos(Pi)
Called as True power

Mar 25, 2008
5
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4. recca02 Senior Member

Apr 2, 2007
1,211
1
An Rms value has the same heating effect as the equivalent d.c value.
http://www.kpsec.freeuk.com/acdc.htm
search for RMS on the above site.
Rms is a type of average value of AC calculated over one cycle.

True power is something else..It is the active power provided to a load.

5. Wendy Moderator

Mar 24, 2008
21,825
3,039
I was looking for RMS, and didn't see it in the choice list. It varies acording to waveform, but for a sine wave it is 1/square root (2). 120VAC is an RMS value, the peak to peak value would be 120 VAC * Square root(2) * 2, or 336V P-P. The 2 is in the equation because without it we would be talking peak voltage, or one side of the sine wave only.

6. thingmaker3 Retired Moderator

May 16, 2005
5,073
8
Last time I checked, cos(pi) was negative one... Effective (aka RMS) value is peak*sqrt(2), as has already been noted.

7. surbhi New Member

Mar 26, 2008
5
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A Root Mean Square (RMS) voltage gives the same heating effect as a DC voltage of the same value.

8. JoeJester AAC Fanatic!

Apr 26, 2005
4,072
1,774
RMS = effective.

After all,