Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Thevinin Question (electrical Crts)

  1. Apr 25, 2010 #1
    ok, i want to find a thevinin equvilent so i can replace the circuit at the load with the thevinin equivalent.

    so i would end up with a voltage thevinin, thevinin resistance and the load.

    now i found the thevinin resistance to be 4k ohm.

    now i found the voltage at the load, thus thevinin voltage to be 8 volts.

    the max power through the load is when the load is equal to thevinin resistance which is 4k ohm. i calculated the max power transfered to be 16mW, but they got 4mW...where did i go wrong.

  2. jcsd
  3. Apr 26, 2010 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Education Advisor

    You got everything correct except the power. What exactly did you do to calculate the power?
  4. Apr 26, 2010 #3
    You probably used the Thevenin voltage squared divided by the resistance to calculate the power.You should use the voltage drop across the resistance instead, wich should be noted to be half the supply voltage, since the two resistances are equal (Rl = Rth) so the voltage drop across each one should be the same.
    Or maybe you just made a mistake with the numbers.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook