Full Wave Rectifiers Vs. Bridge Rectifiers
Full Wave rectifiers Vs. Bridge rectifiers
Full Wave rectifiers
Let take an example were the circuit employs two diodes D1 and D2 with centre tapped transformer. When the centre tap is grounded, the voltages at the opposite ends of the secondary are 180 degree out of phase with each other. During the positive half cycle of secondary, voltage at point A (Any Point in the circuit) swings positive with respect to ground O, the voltage at point B swings negative. The diode D1 at that time becomes forward biased and diode D2 is reverse biased. Hence diode D1 conducts while diode D2 does not. The current flows through diode D1 to load resistor RL during the upper half of secondary winding .
During the negative half cycle of secondary, voltage at point A swings negative with respect to ground O, the voltage at point B swings positive. The diode D2 at that time becomes forward biased and diode D1 in reverse biased, Hence diode D2 conducts while diode D1 does not. The current flow through diode D2 to load resistor RL during the lower half of secondary winding. The current in the load RL is in the same direction for both half cycles of input AC voltage. Therefore DC is obtained across the load RL.
Advantages of Full wave rectifier
• Rectifier efficiency is 81.2%.
• Ripple frequency is two times the input frequency.
• Ripple factor of full wave is 0.48.
Disadvantages of Full wave Rectifier
• It is difficult to locate the centre tap on the secondary winding.
• The DC output is small as each diode utilizes only one half of the transformer's secondary Voltages.
• The diodes used have high peak inverse voltage.
It contains four diodes D1, D2, D3 and D4 connected to form bridge . The AC supply to be rectified is applied to the diagonally opposite ends of the bridge through the transformer. Between other two ends of the bridge, the load resistance RL is connected.
Advantages of Bridge Rectifiers
• The need for center tapped transformer is eliminated.
• The output is twice that of the center-tap circuit for the same secondary voltage.
• The PIV is one half that of the center tap circuit.
Disadvantages of Bridge Rectifiers
• The only Disadvantage of using Bridge rectifiers is that it requires four Diodes.
Reasons for Using a Rectifier
Rectifiers are mainly used for the conversion of an AC power supply into a DC power supply. This is important in many types of applications with old and new electronics. Any of today’s AM/FM and shortwave radios have an adapter when plugged into the wall AC outlet. These are called wall warts, those block type plugs, and they are also rectifiers. This converts the AC power to DC for the radio to operate.
Rectifiers are also used in radios to detect the radio signals and convert them so the radio can receive a station. Rectifiers can be made of solid state diodes, vacuum tube diodes, mercury arc valves, and other technologies.
If you need to buy any type of rectifier, Radio Shack sells all types of rectifiers.