Potential dividers

Starter Formulae True False

I=Qt

VЄ=Q

P=IV

P/I2 =R

I = Є ( R+r )

I = nAVe

W=VQ

RL/A = ρ

W = VIt

Starter Formulae True False

I=Qt *

VЄ=Q *

P=IV *

P/I2 =R *

I = Є ( R+r ) *

I = nAVe *

W=VQ *

RL/A = ρ *

W = VIt *

Learning objectives

• Recall electricity formulae• Draw a potential divider circuit• Explain how a potential divider circuit works• Select and use the potential divider equation

Sometimes only part of the voltage in a circuit is wanted. To allow us to do this we can use a potential divider circuit

V

6V100Ω

100Ω

Here is a simple potential divider circuit. What would you expect the voltage to read? 3V

100Ω

+6V0V

3V

400Ω

+6V0V

4V

200Ω

2V

400Ω

+10V0V

8V

100Ω

2V

+10V

453Ω

+6V0V

??V

138.21Ω

??V

Vin

Vout

R1

R2

𝑉𝑜𝑢𝑡=𝑉𝑖𝑛 𝑥𝑅1

𝑅1+𝑅2

1120 W

120 W

Voltage in

Voltage out

1

1120 W

160 W

Voltage in

Voltage out

2

1120 W

180 W

Voltage in

Voltage out

3

1160 W

180 W

Voltage in

Voltage out 2

4

Voltage out 1

Where and how can we use potential dividers?

hints