x

Real sources and lost volts

Real sources and lost volts

Circuit model of a real cell with e.m.f. E, internal resistance r, load R, current I, lost volts Ir, and a V-against-I graph showing intercept E and gradient -r A source of e.m.f. transfers energy to charge. Its e.m.f. EEE is the energy supplied per unit charge, so it is measured in volts, V. Despite the name, e.m.f. is not a force.

Internal resistance Lesson

  1. A Level
  2. /Physics
  3. /Internal resistance