Electronic – Formulae for induced back-EMF

inductorreactance

I'm doing AC theory, and I'm looking for different formula to find induced back-EMF. Given inductance, voltage, current, frequency, I'm able to find inductive reactance, current and voltage on each inductor, but I'm really struggling to find something to help me put it together. If anyone has any tips at all they would be greatly appreciated!

Best Answer

For an inductor V = \$L\dfrac{di}{dt}\$

This is fundamental and always correct. For instance: -

  • If applied voltage is constant at 1V, current ramps linearly from 0 to infinity at a rate of 1/L amps per second. If L is 0.1 henries it ramps at 10 amps per second
  • If applied voltage is a 5 Vpk sinewave of 1 radian per second then the differential of current is also a sinewave but with peak value of 5/L
  • If the differential of current is a sinewave then current is a cosine wave i.e. it lags the voltage by 90 degrees.

Does this help?