Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

220V is it Rms or peak ??

Status
Not open for further replies.

ysenthilece

Member level 3
Joined
Aug 15, 2005
Messages
56
Helped
2
Reputation
4
Reaction score
0
Trophy points
1,286
Location
india
Activity points
1,962
220v rms

sorry for this silly question .but i can't find the answer anywhere..
 

jeffttan

Member level 2
Joined
Jul 3, 2005
Messages
44
Helped
3
Reputation
6
Reaction score
1
Trophy points
1,288
Activity points
1,671
220v rms?

It is in RMS... same as 110V in power lines
 

electronics_kumar

Advanced Member level 2
Joined
Nov 29, 2004
Messages
659
Helped
34
Reputation
68
Reaction score
9
Trophy points
1,298
Location
Tamilnadu
Activity points
5,552
relation between rms and peak

moreover .why it should be RMS ....why should not as +340V,-340V while referring
 

Eric Best

Member level 4
Joined
Sep 3, 2001
Messages
78
Helped
25
Reputation
50
Reaction score
13
Trophy points
1,288
Activity points
1,044
relation between rms and peak voltage

electronics_kumar said:
moreover .why it should be RMS ....why should not as +340V,-340V while referring

because, simply said, this value (rms) is sort of a mean value which is engaged in, especially, power calculations, etc.

e.g. for resistive loads power can be simply calculated multiplying current and voltage rms values: P = Vrms * Irms, whatever waveform it represents!
(or P = Vrms*Vrms/Rload, or P = Irms*Irms*Rload, likewise with dc values)

Referring to the peak value (only for sine waveforms!!!) power would be calculated:
P = Vpeak * Ipeak / 2 (or P = Vrms*Vrms/(2*Rload), or P = Irms*Irms*Rload/2)

It allows to compare or evaluate "power contents" of different waveforms in a way, while its peak values don't give any information as to this point.

Best Regards
Eric
 

the_risk_master

Advanced Member level 2
Joined
Aug 12, 2005
Messages
662
Helped
79
Reputation
158
Reaction score
19
Trophy points
1,298
Location
UE+MIT, Philippines, (14°N , 120°E )
Activity points
5,527
rms 220v

Try to grab a Digital Multimeter (select it as to measure AC voltage with range of at least higher on what you are expected to measure) Now read the Meter, it should read 220V (note all meter device should read RMS values)
 

Eric Best

Member level 4
Joined
Sep 3, 2001
Messages
78
Helped
25
Reputation
50
Reaction score
13
Trophy points
1,288
Activity points
1,044
220 vrms

the_risk_master said:
Try to grab a Digital Multimeter (select it as to measure AC voltage with range of at least higher on what you are expected to measure) Now read the Meter, it should read 220V (note all meter device should read RMS values)

To tell the truth the above is not always true. Multimeters usually display rms value but this fact does not mean they really measure it. If they do, you can see the notice "True RMS" somewhere on the device and such a device is also appropriately more expensive (it requires a built-in rms converter). Other devices usually measure peak or mean value of a rectified waveform and take advantage of the fact that the relations between peak/mean and rms (root mean square) values for a known waveform, in this case sine wave, are constants so that they can recalculate it and display. This fact implies that such a device displays the more inaccurate value (sometimes really nonsens) the more the measured waveform "differs" from sine wave.
For instance waveforms in circuits with a phase controlled SCR (thyristor or triac) give quite big errors measured with non-true rms devices.

Just for interest, the mentioned values are defined as follows:
For periodic waveforms v(t):

mean value = \[\frac{1}{T}\int_0^T{v(t)dt}\]


rms value = \[\sqrt{\frac{1}{T}\int_0^T{v^2(t)dt}}\],

where T is the time period.

Sine wave:
If v(t) = M×sin(ωt),
where M ... peak value of the sine wave,
ω = \[2\p f\] =&nbsp\[\frac{2\p}{T}\] ... circular frequency, we obtain:

mean value = 0

if fully rectified, then

mean value = \[\frac{2M}{\p}\] = 0.637M ... relation between mean (fully rectified) and peak value

rms value = \[\frac{M}{\sqrt{2}}\] = 0.707M ... relation between rms and peak value

rms/mean (fully rect.) = \[\frac{\p}{2\sqrt{2}}\] = 0.707/0.637 = 1.11 ... relation between rms and mean value of fully rectified sine wave

Best Regards
Eric
 
Last edited by a moderator:

xjackal

Full Member level 3
Joined
Jan 21, 2004
Messages
163
Helped
20
Reputation
40
Reaction score
8
Trophy points
1,298
Activity points
1,298
sin rms peak

Root Mean Square
 

ziyas

Member level 1
Joined
Dec 16, 2005
Messages
39
Helped
3
Reputation
6
Reaction score
0
Trophy points
1,286
Activity points
1,696
220 v peak to peak

ysenthilece said:
sorry for this silly question .but i can't find the answer anywhere..
this value is its rms it means root mean square so we calculate power from this values of voltage and current directly
 

ba33e

Newbie level 1
Joined
Feb 12, 2007
Messages
1
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,284
relation between rms and peak value

220 is rms.peak voltage is 1.4*220=308v
 

Ilokesh

Newbie level 3
Joined
Feb 11, 2007
Messages
4
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,296
rms voltage 220v

it is a RMS voltage
 

Yarafat

Junior Member level 3
Joined
Jan 30, 2007
Messages
30
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Activity points
1,422
i rms i peak

it is exaclty rms (root mean square) and it peak voltage is √2×220 (v).
 

Eric Best

Member level 4
Joined
Sep 3, 2001
Messages
78
Helped
25
Reputation
50
Reaction score
13
Trophy points
1,288
Activity points
1,044
it(rms) scr calculation

Are you collecting points or what?

STOP these stupid messages, everybody already KNOWS it is rms!!!
 

maharshi_qis

Full Member level 5
Joined
Feb 14, 2007
Messages
241
Helped
13
Reputation
26
Reaction score
6
Trophy points
1,298
Activity points
2,462
calculate 220 rms peak value

if its a sine wave its rms value..
if its a nonsinusoidal wave it wont be RMS...any way becoz every wave can be converted as composition of sine wave there is a true rms meter which gives rms for any wave..gen all ac and dc volts xpressed in rms ..
 

aash32

Newbie level 6
Joined
Aug 20, 2006
Messages
11
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,333
310v sine rms

It should be rms.
 

vaibhav.k

Advanced Member level 4
Joined
Apr 12, 2006
Messages
114
Helped
9
Reputation
18
Reaction score
3
Trophy points
1,298
Location
India
Activity points
1,779
26 vrms vs peak

Its RMS .Please check BL thereja u can get all the details.
 

FANT

Advanced Member level 1
Joined
Feb 27, 2002
Messages
415
Helped
52
Reputation
104
Reaction score
37
Trophy points
1,308
Location
Italy
Activity points
3,653
220v rms peak

It is RMS, the peak voltage is RMS * sqare root o f2, say about 310 V.
The multimeters ( low price ) usually rectify the voltage ( taking the peak voltage ) and then they divide it by SQRT of 2.

Mandi
 

asas

Newbie level 4
Joined
Feb 17, 2007
Messages
7
Helped
1
Reputation
2
Reaction score
1
Trophy points
1,283
Location
Portugal
Activity points
1,304
p=vrms*irms

It's RMS!
Low price multimeters aren't True RMS, but if the signal you are messuring it's a Sine Wave there's no problem!! If not, the values shown would not be correct.........

rms.gif
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top