AC electricity

Question 1

What are the UK mains ratings?

Answer 1

50Hz and 230V rms

Question 2

What is the rms value?

Answer 2

The DC Voltage that provides the equivalent power output as the AC signal

Question 3

What is the average power?

Answer 3

Peak power / 2

Question 4

What are the transformer efficiency equations?

Answer 4

ONLY if efficiency = 100%:
Is/Ip = Vs/Vp = Ps/Pp

Otherwise:
Efficiency = Ps/Pp = VsIs / IpVp

Question 5

How does a soft iron core increase efficiency in a transformer?

Answer 5

More easily magnetised and directs the magnetic flux

Looses less charge upon magnetisation and maximum flux is experienced

Question 6

How is efficiency improved in a transformer?

Answer 6

low resistivity windings, laminated core, soft iron core

Question 7

How does a laminated core effect transformer efficiency?

Answer 7

Layers of iron alternate with an insulator meaning large eddy currents cannot form and the resultant field is at a maximum.