1. Ohm’s Law Resistance in Series Circuits
Resistance in Parallel Circuits
Total Resistance
Equivalent Resistance
Voltage Drops and Resistance
Conductance and Current Flow

2. Resistance in Series Circuits
Key Point:
In a series circuit the total resistance equals the sum of the individual resistances.
RT = R1 + R RN

3. Resistance in Parallel Circuits
Key Point:
Conductance is the reciprocal of resistance.
In a parallel circuit the total conductance equals the sum of the individual branch conductances.
GT = G1 + G2 +…+ GN

4. Total Resistance RULE 11-1
To find the total resistance in a series‑parallel circuit:
Determine which resistors are in parallel and reduce that part of the circuit to an equivalent resistance;
Add series resistances when possible;
Continue steps I and 2 until the circuit is reduced to one resistance.

5. Equivalent Resistance

6. Voltage Drops and Resistance
Key Point:
In a series circuit the greater voltage drops across the greater resistance.
If R1 > R2, then V1 > V2

7. Conductance and Current Flow
Key Point:
In a parallel circuit the greater current flows through the greater conductance.
If G1 > G2, then I1 > I2