application of p-n junction diode ch 3

Question 1

What is rectifier?

Answer 1

electrical device made of many diodes that converts AC to DC

Question 2

Why do we need rectifier?

Answer 2

All battery operated devices need DC supply, but the one we get at home is AC. We use a device called adaptor for charging called adaptor, it has rectifier with other electronic components to convert 220v AC to 5V DC.

Question 3

Difference b/w HWR & FWR

Answer 3

HWR converts half of the AC wave into DC signal.
FWR converts complete AC signal into DC.

Question 4

HWR working

Answer 4

during + half cycle anode will be + & cathode will be - , known as forward
bias , allows the positive cycle to flow
through.
during - half cycle anode will be - & cathode will be + , known as reverse bias , the diode will block the negative cycle.

Question 5

HWR Advantages & Disadvantages?

Answer 5

advantages: *simple circuit. *low cost *easy to use *easy to construct
disadvantages: *high ripple factor *low rectification efficiency *low transformer utilization factor *low power output

Question 6

What’s a Center-Tap transformer?

Answer 6

a dual-voltage transformer that has two inputs (I1 & I2) and three output terminals (T1, T2, T3). The T2 terminal is connected to the center of the output coil which acts as a reference ground (o volt reference).
The T1 terminal produces positive voltage and
the T3 terminal produces negative voltage with respect to the T2.

Question 7

What’s a Center-Tap rectifier?

Answer 7

type of full-wave rectifier uses a center-tap transformer & two diodes

Question 8

Working of Center-Tap rectifier

Answer 8

*During the input positive half cycle T1
will produce positive voltage and T3 will produce a negative voltage.The diode D1 will become forward bias & diode D2 will become reverse bias.This makes a close path from T1 to T2 through the load resistor RL.
*during the input negative half cycle, T1
will generate negative voltage & T3 will
generate a positive voltage. diode D1 will be reverse bias & diode D2 will be in forward bias. current takes the path from T3 to T2

Question 9

Advantages & Disadvantages of a center-tapped FWR:

Answer 9

Advantages: *low ripple factor *high dc output voltage and dc load current value *high rectification efficiency *high output efficiency
Disadvantages: *expensive *difficult to locate the center on the secondary for the tapping. *transformer utility factor is low because only half of the transformer’s secondary winding is used to supply power to the load. *The Peak Inverse Voltage (PIV) of the diode used twice that of the diode used in the half-wave rectifier so the diode used must have high PIV.

Question 10

Working of bridge rectifier?

Answer 10

uses 4 diodes to convert both half cycle of AC input into DC input. During input positive half cycle, the diode D1 & D3 becomes forward bias while D2 & D4 becomes reverse bias. The diode D1 & D2 form a closed loop that provides a positive output voltage across the load resistor RL.
During the negative half cycle, the diode D2 & D4 becomes forward bias while D1 & D3
becomes reverse bias. But the polarity across the load resistor RL remains the same and
provides a positive output across the load.