Hey there! Sign in to join this conversationNew here? Join for free

Alternating Currents Watch

Announcements
    • Thread Starter
    Offline

    16
    ReputationRep:
    Why does the rms of alternating current equal the value of dc in a dc circuit for the same power?
    Offline

    3
    ReputationRep:
    (Original post by Paranoid_Glitch)
    Why does the rms of alternating current equal the value of dc in a dc circuit for the same power?
    A good question. This first post on here explains it well talking about RMS voltage (which is equally applicable to current).

    https://www.quora.com/Is-DC-voltage-...f-yes-then-how

    If you're unsure with what he says, ask me and I'll try to clarify it
    • Study Helper
    Offline

    21
    ReputationRep:
    (Original post by Paranoid_Glitch)
    Why does the rms of alternating current equal the value of dc in a dc circuit for the same power?
    The r.m.s. value is quoted as a d.c. equivalent of the averaged a.c. signal.

    In other words, the r.m.s. value of a time varying non-uniform amplitude/frequency a.c. signal is such that an equivalent d.c. value would produce the same power dissipation in a given load.

    It's a bit like saying the power output of a horse ploughing various fields in different weather conditions averaged over a time period is the equivalent of a 750W d.c. motor operating continuously with a constant load.

    The former is hard to define without quoting complex measurement conditions, the latter is almost trivial and simplifies analysis and computations.
 
 
 
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • Poll
    Will you be richer or poorer than your parents?
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

    Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

    Quick reply
    Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.