110 Volts same as 117 Volts rms??????

Discussion in 'Amps and Cabs [BG]' started by Jennifer, Jan 17, 2001.

  1. Jennifer


    Jul 31, 2000
    Erie, Illinois
    110 Volts is the same as 117 Volts rms, apparantly. Will someone please explain this to me? What does rms mean?
  2. US household AC voltage started out as 110, then they upped it to 115, then to 120. All these numbers are RMS, root mean square, which is the DC equivalent voltage that would dissipate the same amount of power in a resistor. Houselhold AC is really a 60Hz sine wave with a peak positive value of 169 Volts and a peak negative value of -169 Volts. If you hooked this AC across a big 100 Ohm resistor, the resistor would get as hot as it would if it were hooked across a 120V DC battery. Math rocks.

    Depends on how old the equipment is, who labeled it, etc. Pretty much everyone calls it 120 nowadays. They used to call it 110, 115, 117. It's all the same stuff. If it's really old equipment designed for 110, then 120 might stress some of the old components, otherwise it's all the same.

    Is that enough info?