10-08-2012, 03:55 PM
MATERIAL AND METHODS
[attachment=30999]
CENTRE TAP TRANSFORMER
In electronics, a center tap is a connection made to a point half way along a winding of a transformer or inductor, or along the element of a resistor or a potentiometer. Taps are sometimes used on inductors for the coupling of signals, and may not necessarily be at the half-way point, but rather, closer to one end.
Inductors with taps also permit the transformation of the amplitude of alternating current (AC) voltages for the purpose of power conversion, in which case, they are referred to as autotransformers, since there is only one winding. An example of an autotransformer is an automobile ignition coil. Potentiometer tapping provides one or more connections along the device's element, along with the usual connections at each of the two ends of the element, and the slider connection. Potentiometer taps allow for circuit functions that would otherwise not be available with the usual construction of just the two end connections and one slider connection.
volt center tapped
Volts center tapped (VCT) describes the voltage output of a center tapped transformer. For example: A 24 VCT transformer will measure 24 VAC across the outer two taps (winding as a whole), and 12 VAC from each outer tap to the center-tap (half winding). These two 12 VAC 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.
Application
One of the major applications of the centre tap transformer is using diodes circuits. The working of the combined effect of the diodes and the transformer are explained next.
RECTIFICATION
Simply def ined, rectification is the conversion of alternating current (AC) to direct current (DC). This involves a device that only allows one-way f low of electrons. The most popular application of the diode is rectification.
As we have seen, he full use of both half-cycles of the sine wave, a different rectifier circuit configuration must be used. Such a circuit is called full -wave rectifier . One kind of full-wave rectifier, called the center-tap design, uses a transformer with a center-tapped secondary winding and two diodes as :
RECTIFIER CIRCUIT OPERATION
Consider the first half-cycle, when the source voltage polarity is positive (+) on top and negative (-) on bottom. At this time, only the top diode is conducting; the bottom diode is blocking current, and the load ´the first half of the sine wave, positive on top and negative on bottom. Only the top half of the transformer's secondary winding carries current during this half-cycle.
cycle of input
During the next half-cycle, the AC polarity reverses. Now, the other diode and the other half of the transformer's secondary winding carry current while the por tions of the circuit formerly carrying current during the last half-cycle sit idle. The load still sees´ half of a sine wave, of the same polarity as before positive on top and negative on bottom.
Thus we can see that due to the joint effect of the transformers and diodes the rectification Is successfully done. This rectifier circuit is going to give an input.To charge the battery back up to a certain point.
CAPACITOR FILTER
This is the most simple form of the filter circuit and in this arrangement a high value capacitor C is placed directly across the output terminals in order to reduce the ripple components in the DC output of the filter .During the conduction period it gets charged and stores up energy to it during non-conduction period. But the discharging time is quite large (roughly 100times more than the charging time depending upon the value of R ). Because I it discharges through load resistance R. Large the value of capacitor C more it offers a low impedance shunt path of the ac components or ripples but offers high impedance to the dc component. Thus ripples get by passed through capacitor C and only dc component flows through the load resistance R .The working is explained using a series of diagrams.
[attachment=30999]
CENTRE TAP TRANSFORMER
In electronics, a center tap is a connection made to a point half way along a winding of a transformer or inductor, or along the element of a resistor or a potentiometer. Taps are sometimes used on inductors for the coupling of signals, and may not necessarily be at the half-way point, but rather, closer to one end.
Inductors with taps also permit the transformation of the amplitude of alternating current (AC) voltages for the purpose of power conversion, in which case, they are referred to as autotransformers, since there is only one winding. An example of an autotransformer is an automobile ignition coil. Potentiometer tapping provides one or more connections along the device's element, along with the usual connections at each of the two ends of the element, and the slider connection. Potentiometer taps allow for circuit functions that would otherwise not be available with the usual construction of just the two end connections and one slider connection.
volt center tapped
Volts center tapped (VCT) describes the voltage output of a center tapped transformer. For example: A 24 VCT transformer will measure 24 VAC across the outer two taps (winding as a whole), and 12 VAC from each outer tap to the center-tap (half winding). These two 12 VAC 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.
Application
One of the major applications of the centre tap transformer is using diodes circuits. The working of the combined effect of the diodes and the transformer are explained next.
RECTIFICATION
Simply def ined, rectification is the conversion of alternating current (AC) to direct current (DC). This involves a device that only allows one-way f low of electrons. The most popular application of the diode is rectification.
As we have seen, he full use of both half-cycles of the sine wave, a different rectifier circuit configuration must be used. Such a circuit is called full -wave rectifier . One kind of full-wave rectifier, called the center-tap design, uses a transformer with a center-tapped secondary winding and two diodes as :
RECTIFIER CIRCUIT OPERATION
Consider the first half-cycle, when the source voltage polarity is positive (+) on top and negative (-) on bottom. At this time, only the top diode is conducting; the bottom diode is blocking current, and the load ´the first half of the sine wave, positive on top and negative on bottom. Only the top half of the transformer's secondary winding carries current during this half-cycle.
cycle of input
During the next half-cycle, the AC polarity reverses. Now, the other diode and the other half of the transformer's secondary winding carry current while the por tions of the circuit formerly carrying current during the last half-cycle sit idle. The load still sees´ half of a sine wave, of the same polarity as before positive on top and negative on bottom.
Thus we can see that due to the joint effect of the transformers and diodes the rectification Is successfully done. This rectifier circuit is going to give an input.To charge the battery back up to a certain point.
CAPACITOR FILTER
This is the most simple form of the filter circuit and in this arrangement a high value capacitor C is placed directly across the output terminals in order to reduce the ripple components in the DC output of the filter .During the conduction period it gets charged and stores up energy to it during non-conduction period. But the discharging time is quite large (roughly 100times more than the charging time depending upon the value of R ). Because I it discharges through load resistance R. Large the value of capacitor C more it offers a low impedance shunt path of the ac components or ripples but offers high impedance to the dc component. Thus ripples get by passed through capacitor C and only dc component flows through the load resistance R .The working is explained using a series of diagrams.