Series Circuit Two elements are in series if They have only one terminal in common. The common point in the two elements is not connected to a third current carrying element.
Resistance Resistance is proportional to length length direction of current flow
Resistance R = ρ L/A ρ is the resistivity of the material (units?)
Resistance What happens if two elements are connected back to back? length direction of current flow length direction of current flow
Resistance R = ρ (L 1 +L 2 )/A R = R 1 + R 2 The total resistance of a series circuit is the sum of all the resistances in the path
Resistance The resistance seen by the source R=R 1 +R 2 The two circuits on the right are equivalent R1R1 R2R2 R 1 +R 2
Voltage Drop? The current through each resistor is calculated by the Ohm’s law =V 1 /R 1 Where V 1 is the voltage across the resistor. =V/R T Where R T is the total resistance in the circuit. V 1 = VxR 1 /R T
Power? Power dissipated in each resistor P 1 = V 1 2 /R 1 P 1 = (V 2 /R T 2 )x R 1 Total power = V 2 /R T = P 1 + P 2 + …
Kirchhoff’s Voltage Law The algebraic sum of the potential rises and drops around a closed loop is zero.
KVL V + V 1 +V 2 = 0 Can anyone prove this mathematically? R1R1 R2R2 V V1V1 V2V2
Voltage Divider Rule In a series circuit the voltage across the resistive elements will divide as the magnitude of the resistors
Ground Terminal This is not a loop. Or is it?
Ground Terminal This is not a loop. Or is it? Ground terminal means that the two points are both connected to ground and are at a zero potential. So this is a loop.
Internal Resistances Voltage and other sources have internal resistances, and they should be counted while solving circuits.