Ohm

1
Ohms 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 R2 . . . 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 gt R2, then V1 gt V2
7
Conductance and Current Flow
Key Point In a parallel circuit the greater current flows through the greater conductance. If G1 gt G2, then I1 gt I2