electrical theory
- Thread starter ib26ew
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electricman2
Senior Member
- Location
- North Carolina
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- Retired Electrical Contractor
Re: electrical theory
RMS stands for Root Mean Square and represents the effective value of voltage or current for alternating current. I believe it is 0.707 of the peak value.
RMS stands for Root Mean Square and represents the effective value of voltage or current for alternating current. I believe it is 0.707 of the peak value.
bphgravity
Senior Member
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- Florida
Re: electrical theory
The value of RMS (root mean square) is .707 of the peak value. Or, the peak value is 1.414 x the RMS (effective value).
This is considered the effective value in that .707A of current generates the same heat as 1A of Direct Current.
[ August 05, 2004, 08:49 PM: Message edited by: bphgravity ]
The value of RMS (root mean square) is .707 of the peak value. Or, the peak value is 1.414 x the RMS (effective value).
This is considered the effective value in that .707A of current generates the same heat as 1A of Direct Current.
[ August 05, 2004, 08:49 PM: Message edited by: bphgravity ]
Re: electrical theory
imagine the area of a sine wave being converted to a square wave of equal area; it maintains a constant voltage value along its peak. That peak is the root mean square of the sine wave of equal area. The sine wave peak of 120 volt square wave is over 170 volts for each half of its cycle.
paul
imagine the area of a sine wave being converted to a square wave of equal area; it maintains a constant voltage value along its peak. That peak is the root mean square of the sine wave of equal area. The sine wave peak of 120 volt square wave is over 170 volts for each half of its cycle.
paul
Ed MacLaren
Senior Member
Re: electrical theory
ib26ew,
Below is part of a "non-technical" explanation that I often use with my apprentices.
Hope it helps.
Ed
RMS (Effective) value means "having the same effect in a resistive load as an equivalent value of DC voltage or current".
120 volts AC (rms) will produce the same amount of heat in a heater as 120 volts DC would, if applied to the same heater, (Fig. 7) but it would have to rise to 170 volts at the peak of each half cycle to make up for the time when it is zero.
Because it does reach the maximum value twice each cycle, some electronic components that are easily damaged must be rated to withstand the maximum value.
[ August 08, 2004, 09:53 AM: Message edited by: Ed MacLaren ]
ib26ew,
Below is part of a "non-technical" explanation that I often use with my apprentices.
Hope it helps.
Ed
RMS (Effective) value means "having the same effect in a resistive load as an equivalent value of DC voltage or current".
120 volts AC (rms) will produce the same amount of heat in a heater as 120 volts DC would, if applied to the same heater, (Fig. 7) but it would have to rise to 170 volts at the peak of each half cycle to make up for the time when it is zero.
Because it does reach the maximum value twice each cycle, some electronic components that are easily damaged must be rated to withstand the maximum value.
[ August 08, 2004, 09:53 AM: Message edited by: Ed MacLaren ]
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