HALF WAVE RECTIFIER
AIM- To Study half wave rectifier (H.W.R.) and calculate its ripple factor.
APPARATUS- Given circuit board, a multimeter, C.R.O, connecting wire etc
INTRODUCTORY INFORMATION- Rectifier is a device which converts A.C power into D.C power. There are three important types of single phase rectifier.
The basic circuit of half wave rectifier with a resistive load is shown in figure. The alternating secondary voltage is applied to a diode connected series with a load resistor RL.
Working: -
During positive half cycle of the input A.C voltage the diode D is forward bias (ON) and conducts. While conducting, the diode acts as a short circuit so that circuit current flows and hence, positive half cycle of the input A.C voltage is dropped across RL which is shown as VL.
During the negative input half cycle the diode in reverse biased (OFF) and so does not conduct i.e. there is no current flow. Hence there is no voltage drop across RL. In other words IL=0 and VL = 0 the output is not steady D.C but only a pulsating D.C waves (without filter) having a ripple frequency equal to that of the input voltage frequency.
PROCEDURE: -
Vdc=Vm/π
Compare this value with the practically measured value of the o/p D.C voltage
Ripple factor= A.C voltage at the output / D.C voltage at output = 1.21
OBSERVATIONS:-
QUANTITY THEROTICAL VALUE PRACTICAL VALUE
RESULT:-
APPARATUS- Given circuit board, a multimeter, C.R.O, connecting wire etc
INTRODUCTORY INFORMATION- Rectifier is a device which converts A.C power into D.C power. There are three important types of single phase rectifier.
- Half wave rectifier
- Full wave rectifier
- Full wave bridge rectifier
The basic circuit of half wave rectifier with a resistive load is shown in figure. The alternating secondary voltage is applied to a diode connected series with a load resistor RL.
Working: -
During positive half cycle of the input A.C voltage the diode D is forward bias (ON) and conducts. While conducting, the diode acts as a short circuit so that circuit current flows and hence, positive half cycle of the input A.C voltage is dropped across RL which is shown as VL.
During the negative input half cycle the diode in reverse biased (OFF) and so does not conduct i.e. there is no current flow. Hence there is no voltage drop across RL. In other words IL=0 and VL = 0 the output is not steady D.C but only a pulsating D.C waves (without filter) having a ripple frequency equal to that of the input voltage frequency.
PROCEDURE: -
- Connect the C.R.O to A.C mains check whether the beam appears on the screen.
- Now connect the C.R.O to the O/P of the rectifier i.e. Across RL.
- Connect the given circuit to A.C mains (see that the filter switch ‘SF’ is OFF).
- Observe the o/p waveform on C.R.O & draw it in your notebook.
- Connect the C.R.O to the secondary of the transformer observe the A.C wave form & draw it in your notebook.
- Now use a multimeter to measure the A.C voltage at the secondary terminals of the transformers. This gives rms value. Also measure the A.C & D.C voltage at the o/p point.
- Multiply this rms value by 2 to get the peak value. Calculate the theoretical value of D.C voltage using formula
Vdc=Vm/π
Compare this value with the practically measured value of the o/p D.C voltage
- Using the measured value of D.C & A.C o/p voltage, calculate the ripple factor. This value should be about 1.21
Ripple factor= A.C voltage at the output / D.C voltage at output = 1.21
OBSERVATIONS:-
- D.C voltage at the output = ---------V
- A.C voltage at the output = ---------V
QUANTITY THEROTICAL VALUE PRACTICAL VALUE
- Output D.C voltage. Vdc= Vm/ π
- Ripple factor. 1.21
RESULT:-
- The wave shape at input & output are observed on the C.R.O they are plotted.
- The output D.C voltage is a little less than the theoretical value.
- There is a little difference between the theoretical value & measured value of ripple factor.