Arrangement of Resistors

Resistors in Series:

When resistors are connected end to end, they are said to be in series.

The current flowing through each resistor is the same but they have a different potential difference.

Total resistance R = R₁ + R₂ + R₃

This can be proven using Ohm's law:

• I = the current flowing through each resistor
• Let the voltage drop across resistor R₁ be V₁
• Let the voltage drop across resistor R₂ be V₂ , also,
• Let the voltage drop across resistor R₃ be V₃
• V = total p.d. across the combined resistors

Therefore the total voltage can then be found;

V = V₁ + V₂ + V₃

Using Ohm's law:

V = IR

R = combined resistance

∴ IR = IR₁ + IR₂ + IR₃

Dividing through by I we then have: