5. An AC voltage is defined as a voltage that periodically reverses
polarity and will cause current to flow in the reverse direction.
A DC voltage is a voltage that does not reverse direction, and
causes current to flow in one direction only.
When an AC voltage is measured with a voltmeter, the indicated
value will be the RMS value
(V rms = 0.707 x V peak) or (V rms = V peak) of the waveform)
√2
When a DC voltage is measured, the meter will indicate the
average of the DC voltage waveform.
6. Single phase half wave
AC Supply
Load
+
+
-
TIME -
TIME
Revision 01 6
7. Half Wave Single Phase Rectification
V load = V average = 0.318 x V peak or 0 .45 x V rms
fr = fs
PIV = √ 2 x V rms
V ripple = √ 2 x V rms
9. Full Wave Single Phase
Rectification
V load = V average = 0.638 x V peak or 0 .9 x V rms
fr = 2 x fs
PIV = √ 2 x V rms (bridge rectifier)
PIV = √ 2 x (2 x V rms) (centre tapped rectifier)
V ripple = √ 2 x V rms
10. Single phase bridge rectifier
+
AC Supply -
D D2 TIME
+ 1
- D3 D4
TIME
Load
Revision 01 10
14. Three phase half wave
D
1
3 Phase Supply Load
D2
D3
+ +
- - TIM
E
TIME
Revision 01 14
15. Half Wave Three Phase
Rectification
V load = V average = 0.827 x V peak or 1.17 x V rms
fr = 3 x fs
PIV =2.45 x V phase rms (√ 2 x√ 3 x V rms)
V ripple = 0.707 x V rms
16. Three phase full wave
Suppl
y
D D3
D2
1
+
- TIM
E
D4 D5 D
6
+
-
TIME
Revision 01 16
17. Full Wave Three Phase
Rectification
V load = V average = 0.955 x V peak or
1.34 x V line rms or 2.34 x V phase rms
fr = 6 x fs
PIV =√ 2 x V line rms
V ripple = 0.16 x V rms