Experiment 8 - Series Circuit of Real Batteries

Real batteries have an internal resistance. What are the implications for a series circuit of several real batteries?

A real battery can be described as an ideal battery with a 0 Ω resistance and an internal resistance R_i in series. When you connect several real batteries together in a series circuit, the total internal resistance is the sum of the individual internal resistances...

Ri = R1i + R2i + R3i + ... For the example shown of three 9 V batteries with internal resistance of 1.2 W the total voltage becomes...

Three real batteries in a series circuit.

U_total = U₁ + U₂ + U₃ = 9 V + 9 V + 9V = 27 V

and a total internal resistance of...

R_i = R1_i + R2_i + R3_i = 1.2 Ω + 1.2 Ω + 1.2 Ω = 3.6 Ω

And how act several batteries connected in a parallel circuit?