Now, this capacitor will get charged upto 12V dc as both are connected with the common terminal of a transformer. The connection of both capacitors are such that the common terminal of the capacitors is connected directly to the centre terminal of the centre tapped transformer. Now, two filter capacitor of rating 2200uF and 25 V are used as shown in circuit diagram. So, to remove ripples from the supply, filter capacitors are used. Now, 24V dc output which contains peak to peak ripples can’t be connected directly to the load. Step-III: Filter the Ripples from the output: The output of rectifier is not pure dc, but it contains ripples in it. Generally, because of surges in current, it is possible to damage the diode, if we used low ampere rating diode. It is not necessary to use this much of high current capacity diode but because of safety and flexibility purpose, high current capacity diode is used. In this Dual Power Supply Circuit, Diode bridge rectifier is made up of 6A four power diodes. The waveform of input and output voltage of full bridge rectifier is as shown below. V DC = 2Vm / Π where, Vm=peak value of ac supply voltage and Π is Pi So, number of diodes are 4 and input voltage (24V ac) and output voltage is also 24V dc with ripples in it.įor, full bridge rectifier output voltage, In full bridge rectifier, number of diodes is 4 and it is connected as shown in figure and output voltage is same as the input voltage. For example, if input voltage is 24V, then output dc voltage is 12V and number of diode used in this type of rectifier is 2. In half bridge rectifier, output voltage is half of the input voltage. To convert ac into dc, we can make two types of rectifiers, one is half bridge rectifier and second is full bridge rectifier. It is generally made up of diode switches as shown in Circuit Diagram. Rectifier circuit is a converter, which converts ac supply in to dc supply. The outer two terminals of the centre tapped transformer are connected to the bridge rectifier circuit. Step – II: Converting 12v AC into 12v DC using Full Bridge Rectifier OUTPUT: Between outer terminal and middle terminal: 12V ac, 50 Hzīetween two outer terminals: 24V ac. The advantage of using a centre tapped transformer is we can get the both +12V and -12V dc supply using only one transformer. These two 12V ac supplies are 180 degrees out of phase with each other, thus making it easy to derive positive and negative 12 volt dc power supplies from them. For example: A 24V centre tapped transformer will measure 24V ac across the outer two taps (winding as a whole), and 12V ac from each outer tap to the center-tap (half winding). The centre tapped describes the voltage output of a center tapped transformer. The primary terminals of the centre tapped transformer is connected with household supply (220V ac, 50Hz) and output is taken from secondary terminals of the transformer. Step-I: Converting 220v AC into 12v AC using Step Down Transformer Lastly, the output of the capacitor that is pure DC is given to voltage regulator IC 7812 and IC7912 which will regulate the output voltage at 12V and -12V DC, despite the change in input voltage.To filter out these ripples, capacitor of 2200 uf, 25V is used. The output of the rectifier circuit that is DC contains the ripples in the output voltage. Secondly, output of this transformer is given to the rectifier circuit, which will convert the ac supply into dc supply.Firstly, 220V AC is converted into 12V AC by using simple step-down (220V/12V) transformer.This can be achieved in simple three steps: The objective of this project is to convert 220V AC supply in to +12V and -12v DC supply, that is why it is named Dual Power Supply as we get positive and negative 12v power supply at the same time.
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