__HALF – WAVE RECTIFIER__

__AIM__*: - T*o obtain the load regulation and ripple factor of a half-rectifier

*.*

*1*

*.*with Filter

2. without Filter

__APPARATUS:-__**Experimental Board**

Multimeters –2No’s.

Transformer (6-0-6).

Diode, 1N 4007

Capacitor 100μf.

Resistor 1KΩ.

Connecting wires

__THEORY__**: -**

During positive half-cycle of the input voltage, the diode D1 is in forward bias and conducts through the load resistor R1. Hence the current produces an output voltage across the load resistor R1, which has the same shape as the +ve half cycle of the input voltage.

During the negative half-cycle of the input voltage, the diode is reverse biased and there is no current through the circuit. i.e, the voltage across R1 is zero. The net result is that only the +ve half cycle of the input voltage appears across the load. The average value of the half wave rectified o/p voltage is the value measured on dc voltmeter.

For practical circuits, transformer coupling is usually provided for two reasons.

1. The voltage can be stepped-up or stepped-down, as needed.

2. The ac source is electrically isolated from the rectifier. Thus preventing shock hazards in the secondary circuit.

__CIRCUIT DIAGRAM:-__

__PROCEDURE:-__1. Connections are made as per the circuit diagram.

2. Connect the primary side of the transformer to ac mains and the secondary side to the rectifier input.

3. By the multimeter, measure the ac input voltage of the rectifier and, ac and dc voltage at the output of the rectifier.

4. Find the theoretical of dc voltage by using the formula,

Vdc=Vm/П

Where, Vm=2Vrms, (Vrms=output ac voltage.)

The Ripple factor is calculated by using the formula

r=ac output voltage/dc output voltage.

*REGULATION CHARACTERSTICS:-**1.*Connections are made as per the circuit diagram.

2. By increasing the value of the rheostat, the voltage across the load and current flowing through the load are measured.

3. The reading is tabulated.

4. Draw a graph between load voltage (V

_{L}and load current ( I_{L }) taking V_{L}on X-axis and I_{L}on y-axis5. From the value of no-load voltages, the %regulation is calculated using the formula,

__Theoretical calculations for Ripple factor:-__

__Without Filter__*:-* Vrms=Vm/2

Vm=2Vrms

Vdc=Vm/П

Ripple factor r=√ (Vrms/ Vdc )

^{2 }-1 =1.21

__With Filter__**:-**

Ripple factor, r=1/ (2√3 f C R)

*Where f =50Hz*

C =100µF

**R**

_{L}=1KΩ

**:-**

__PRACTICAL CALCULATIONS__ Vac=

Vdc=

Ripple factor with out Filter =

Ripple factor with Filter =

__OBSERVATIONS:-__**WITHOUT FILTER**

USING DMM | V_{ac}(v) | V_{dc}(v) | r= V/_{ac} V_{dc} |

| | |

**WITH FILTER**

USING DMM | V_{ac}(v) | V_{dc}(v) | r= V/_{ac} V_{dc} |

| | |

**WITHOUTFILTER:-**

Vdc=Vm/П, Vrms=Vm/2

*,*Vac=√ ( Vrms^{2}- Vdc^{2}) USING CRO | V_{m}(v) | V_{ac}(v) | V_{dc}(v) | r= V/_{ac} V_{dc} |

| | | |

**WITHFILTER**

USINGCRO | V_{1}(V) | V_{2}(V) | V_{dc}= (V_{1}+V_{2})/2 | V_{ac}=(V_{1- }V_{2})/2√3 | r= V/_{ac} V_{dc} |

| | | | |

__PRECAUTIONS:__1. The primary and secondary sides of the transformer should be carefully identified.

2. The polarities of the diode should be carefully identified.

3. While determining the % regulation, first Full load should be applied and then it should be decremented in steps.

__RESULT__

__:-__1. The Ripple factor for the Half-Wave Rectifier with and without filters is measured.

2. The % regulation of the Half-Wave rectifier is calculated.

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