7.3 voltage and current

http://www.youtube.com/watch?v=-n1pSHzdahc

7.3 Voltage and Current 12 December 2010

The cards have

keywords with more

scientific definitions,

can you match them

up?

The opposition to the flow of

current

The rate of flow of charge

How much energy each charge

carries

All components are in

a single branch

Components are in

multiple branches

Aims

• State the equations of current

and voltage in a series circuit

• Describe the changes in

current and voltage in a series

circuit

• Define current and voltage

For a series circuit:

321 IIII

The current is the same

throughout the circuit

Current is the rate of flow of charge

t

QI

Current

The number of

Coulombs flowing

past a point in the

circuit every second.

I = Q/t

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A

I’m counting

how many

coulombs of

electrons go

past me every

second

1 Amp = 1 coulomb per second

321 IIII

321 VVVV

For a series circuit:

321 VVVV

The total voltage is the sum

of the individual voltages

Voltage(emf)

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V

I’m checking the

difference in

energy (per

coulomb) between

the 2 red arrows

1 Volt = 1 Joule per coulomb

Voltage (p.d.)

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V

I’m checking the

difference in

energy (per

coulomb) before

and after the lamp

1 Volt = 1 Joule per coulomb

Voltage is the energy transferred per charge

Q

WV

321 IIII

321 VVVV

I have learned:

I have learned: