1. 6.1 Alternating current and power
AC is used for power distribution because the peak voltage can be easily
changed using transformers
* An AC repeatedly reverses its direction
* In one cycle the charge carriers move in
one direction then the other.
AC measurements
* Mains frequency is 50 Hz ,
one cycle lasts 1/50 sec
= sec = time period T
Frequency: f (Hz)
f = 1 T
Peak
value
Peak to peak
value

2. 6.1 Alternating current and power
AC is used for power distribution because the peak voltage can be easily
changed using transformers
* An AC repeatedly reverses its direction
* In one cycle the charge carriers move in
one direction then the other.
AC measurements
* Mains frequency is 50 Hz ,
one cycle lasts 1/50 sec
= sec = time period T
Frequency: f (Hz)
f = 1 T
Peak
value
Peak to peak
value

3. 6.1 Alternating current and power
AC is used for power distribution because the peak voltage can be easily
changed using transformers
* An AC repeatedly reverses its direction
* In one cycle the charge carriers move in
one direction then the other.
AC measurements
* Mains frequency is 50 Hz ,
Frequency: f (Hz)
Peak
value
Peak to peak
value

4. 6.1 Alternating current and power
AC is used for power distribution because the peak voltage can be easily
changed using transformers
* An AC repeatedly reverses its direction
* In one cycle the charge carriers move in
one direction then the other.
AC measurements
* Mains frequency is 50 Hz ,
Frequency: f (Hz)

5. 6.1 Alternating current and power
AC is used for power distribution because the peak voltage can be easily
changed using transformers
* An AC repeatedly reverses its direction
* In one cycle the charge carriers move in
one direction then the other.
AC measurements
* Mains frequency is 50 Hz ,
Frequency: f (Hz)
Peak
value

6. 6.1 Alternating current and power
AC is used for power distribution because the peak voltage can be easily
changed using transformers
* An AC repeatedly reverses its direction
* In one cycle the charge carriers move in
one direction then the other.
AC measurements
* Mains frequency is 50 Hz ,
Frequency: f (Hz)
Peak
value
Peak to peak
value

7. 6.1 Alternating current and power
* Mains frequency is 50 Hz ,
one cycle lasts 1/50 sec
= sec = time period T
One cycle
f = 1 T
Peak
value
Peak to peak
value

8. P = I V = I2R R = resistance of heater
6.1 Alternating current and power
The heating effect of an alternating current:
varies according to the square of the current
P = I V = I2R R = resistance of heater
At peak current Io maximum power is supplied = Io2 R
At zero current zero power is supplied
Equal areas above and below mean value
also Av value of a sin 2 plot = 1/2
Mean power supplied = ½ Io2 R

9. P = I V = I2R R = resistance of heater
6.1 Alternating current and power
The heating effect of an alternating current:
varies according to the square of the current
P = I V = I2R R = resistance of heater
At peak current Io maximum power is supplied = Io2 R
At zero current zero power is supplied
Equal areas above and below mean value
also Av value of a sin 2 plot = 1/2
Mean power supplied = ½ Io2 R

10. P = I V = I2R R = resistance of heater
6.1 Alternating current and power
The heating effect of an alternating current:
varies according to the square of the current
P = I V = I2R R = resistance of heater
At peak current Io maximum power is supplied = Io2 R
At zero current zero power is supplied
Equal areas above and below mean value
also Av value of a sin 2 plot = 1/2
Mean power supplied = ½ Io2 R

11. P = I V = I2R R = resistance of heater
6.1 Alternating current and power
The heating effect of an alternating current:
varies according to the square of the current
P = I V = I2R R = resistance of heater
At peak current Io maximum power is supplied = Io2 R
At zero current zero power is supplied
Equal areas above and below mean value
also Av value of a sin 2 plot = 1/2
Mean power supplied = ½ Io2 R

12. P = I V = I2R R = resistance of heater
6.1 Alternating current and power
The heating effect of an alternating current:
varies according to the square of the current
P = I V = I2R R = resistance of heater
At peak current Io maximum power is supplied = Io2 R
At zero current zero power is supplied
Equal areas above and below mean value
Mean power supplied = ½ Io2 R

13. P = I V = I2R R = resistance of heater
6.1 Alternating current and power
The heating effect of an alternating current:
varies according to the square of the current
P = I V = I2R R = resistance of heater
At peak current Io maximum power is supplied = Io2 R
At zero current zero power is supplied
Equal areas above and below mean value
also Av value of a sin 2 plot = 1/2
Mean power supplied = ½ Io2 R

14. 6.1 Alternating current and power

15. 6.1 Alternating current and power

16. 6.1 Alternating current and power

17. 6.1 Alternating current and power

18. 6.1 Alternating current and power

19. 6.1 Alternating current and power

20. The mean power supplied to a resistor:
6.1 Alternating current and power
The mean power supplied to a resistor:

21. The mean power supplied to a resistor:
6.1 Alternating current and power
The mean power supplied to a resistor:

22. 6.1 Alternating current and power

23. 6.1 Alternating current and power