Series

Series

For series calculations:

Step 1: Add resistances.

Step 2: Find current.

Step 3: Find each voltage drop.

Series

This topic applies the rules of series connections to circuit calculations.

For resistors in series:

Rₜ = R₁ + R₂ + ...

Current:

I = I₁ = I₂ = ...

Potential difference:

Vₜ = V₁ + V₂ + ...

Example

A 4 Ω and 8 Ω resistor are connected in series to 24 V.

Total resistance:

**Rₜ = 4 + 8 = 12 Ω**

Current:

**I = VR**

**I = 2412 = 2 A**

Voltage across 4 Ω:

**V₁ = IR₁ = 2 × 4 = 8 V**

Voltage across 8 Ω:

**V₂ = IR₂ = 2 × 8 = 16 V**

Check:

**8 + 16 = 24 V**

Voltage Division

Because the same current passes through both resistors:

**V₁V₂ = R₁R₂**

A larger resistance therefore has a larger voltage drop.

Series — Advanced

Series circuits form a voltage divider because identical current through unequal resistances produces voltage drops proportional to their resistances.