Chapter 10
{ Circuits } (class notes)
Power = measured in Watt
P =
𝑾
Δ𝒕
SWITCH OPEN P = VI
P = I 2R
𝑽2
P = 𝑹
Power in Series &
Parallel circuits
Power of bulb = ‘brightness’
o No current flows
o Voltmeter reads emf
SERIES
➢ Blue = internal circuit
➢ Purple = external circuit
Current = same (constant)
SWITCH CLOSED ➢ P = I2R
➢ ∴P ∝ R
PARALLEL
o Current flows Voltage = same (constant)
𝑽2
o Voltmeter reads voltage to external ➢ P =
circuit (Vex) 𝑹
𝟏
o Voltmeter reading drops bcz ➢ ∴P ∝
𝑹
internal resistance of cells
o ∴ V = lost (Vlost/Vint) – 0,5V is
lost
Energy = required to move charges
REMEMBER:
through cells (w/ resistance) Series
Emf = Vex + Vint • Current = same
3V = 2,5V + 0,5V • Voltage = split
* Vint x measured by voltmeter *
• Resistance incr
E = I(R + r)
{ Circuits } (class notes)
Power = measured in Watt
P =
𝑾
Δ𝒕
SWITCH OPEN P = VI
P = I 2R
𝑽2
P = 𝑹
Power in Series &
Parallel circuits
Power of bulb = ‘brightness’
o No current flows
o Voltmeter reads emf
SERIES
➢ Blue = internal circuit
➢ Purple = external circuit
Current = same (constant)
SWITCH CLOSED ➢ P = I2R
➢ ∴P ∝ R
PARALLEL
o Current flows Voltage = same (constant)
𝑽2
o Voltmeter reads voltage to external ➢ P =
circuit (Vex) 𝑹
𝟏
o Voltmeter reading drops bcz ➢ ∴P ∝
𝑹
internal resistance of cells
o ∴ V = lost (Vlost/Vint) – 0,5V is
lost
Energy = required to move charges
REMEMBER:
through cells (w/ resistance) Series
Emf = Vex + Vint • Current = same
3V = 2,5V + 0,5V • Voltage = split
* Vint x measured by voltmeter *
• Resistance incr
E = I(R + r)
