Voltage Drops in Series Circuits

Total Resistance in Series (Rt)

Sum of individual resistances (R1 + R2 + R3).

Current in a Series Circuit

Current is equal throughout the continuous path (It = I1 = I2 = I3).

Voltage Drop

Electrical energy transferred by each resistor from the shared source.

Calculating Voltage Drop

Calculated using Ohm's Law: V = I × R.

Resistance and Voltage Drop

Larger resistance results in a larger voltage drop.

Kirchhoff's Voltage Law (KVL)

Source voltage equals the sum of the voltage drops (Vt = V1 + V2 + V3).

Measuring Component Voltage

Probes are placed ACROSS the selected resistor.

Multimeter Lead Connections

Black lead to COM, red lead to V/Ω.

Calculated vs. Measured Differences

Caused by resistor tolerance, source setting, leads, and meter resolution.

Effect of an Open Circuit

Stops normal current, causing It ≈ 0 A.

Technician Troubleshooting Steps

Verify, follow, measure, compare, locate, and repair.

Safety Rule for Circuit Changes

Power OFF before resistance, continuity, or circuit changes.