Advertisements
Advertisements
प्रश्न
With the help of neat labelled circuit diagram explain the working of half wave rectifier using semiconductor diode. Draw the input and output waveforms.
Advertisements
उत्तर
A device which converts A.C. to D.C. is called rectifier. In this case output exists only for half cycle hence it is called half wave rectifier. Construction: The circuit diagram of a half wave rectifier using a junctiondiode is as shown in fig. The alternating voltage source is connected to the primary coil of a transformer. The secondary coil is connected to the diode in series with a resistance RL called the load resistance
T=Transformer
D=Diode
V0=output voltage
v1=input votage
RL=load resistance
Working: In first cycle of input voltage, the anode of the diode is positive potential w.r.t. cathode. Hence the diode is in forward-biased. Hence it conduct current. The current flows through load resistance giving voltage drop iRL. This voltage drop is called output voltage. During next half cycle the anode of diode is in negative potential w.r.t. Hence it is in reversed-biased. Hence it does not conduct the current. Hence current does not flow through load resistance giving no P.D. across it. Hence output voltage is unidirectional. It is called as D.C.
APPEARS IN
संबंधित प्रश्न
Explain the working of P-N junction diode in forward and reverse biased mode.
What causes the setting up of high electric field even for small reverse bias voltage across the diode?
When a forward bias is applied to a p-n junction, it ______.
In the following diagram 'S' is a semiconductor. Would you increase or decrease the value of R to keep the reading of the ammeter A constant when S is heated? Give reason for your answer.
Draw its I – V characteristics of photodiode
With reference to semiconductor devices, define a p-type semiconductor and a Zener diode.
What is the use of Zener diode?
Draw a labelled diagram of a full wave rectifier. Show how output voltage varies with time if the input voltage is a sinusoidal voltage.
Show on a graph, the variation of resistivity with temperature for a typical semiconductor.
The plate current in a diode is 20 mA when the plate voltage is 50 V or 60 V. What will be the current if the plate voltage is 70 V?
A triode value operates at Vp = 225 V and Vg = −0.5 V.
The plate current remains unchanged if the plate voltage is increased to 250 V and the grid voltage is decreased to −2.5 V. Calculate the amplification factor.
In semiconductor physics, what is meant by:
(i) rectifier
(ii) an amplifier
(iii) an oscillator
Diffusion in a p-n junction is due to ______.
The current through an ideal PN-junction shown in the following circuit diagram will be:
The drift current in a p-n junction is from the ______.
Use a transistor as an amplition
On increasing the reverse biases voltage to a large value in a P – N junction diode-current
In a semiconductor diode, the barrier potential offers opposition to only
Consider an npn transistor with its base-emitter junction forward biased and collector base junction reverse biased. Which of the following statements are true?
- Electrons crossover from emitter to collector.
- Holes move from base to collector.
- Electrons move from emitter to base.
- Electrons from emitter move out of base without going to the collector.
The breakdown in a reverse biased p–n junction diode is more likely to occur due to ______.
- large velocity of the minority charge carriers if the doping concentration is small.
- large velocity of the minority charge carriers if the doping concentration is large.
- strong electric field in a depletion region if the doping concentration is small.
- strong electric field in the depletion region if the doping concentration is large.
If each diode in figure has a forward bias resistance of 25 Ω and infinite resistance in reverse bias, what will be the values of the current I1, I2, I3 and I4?
In the circuit shown in figure, when the input voltage of the base resistance is 10 V, Vbe is zero and Vce is also zero. Find the values of Ib, Ic and β.
Explain the formation of the barrier potential in a p-n junction.
A semiconductor device is connected in series with a battery, an ammeter and a resistor. A current flows in the circuit. If. the polarity of the battery is reversed, the current in the circuit almost becomes zero. The device is a/an ______.
Read the following paragraph and answer the questions that follow.
| A semiconductor diode is basically a pn junction with metallic contacts provided at the ends for the application of an external voltage. It is a two-terminal device. When an external voltage is applied across a semiconductor diode such that the p-side is connected to the positive terminal of the battery and the n-side to the negative terminal, it is said to be forward-biased. When an external voltage is applied across the diode such that the n-side is positive and the p-side is negative, it is said to be reverse-biased. An ideal diode is one whose resistance in forward biasing is zero and the resistance is infinite in reverse biasing. When the diode is forward biased, it is found that beyond forward voltage called knee voltage, the conductivity is very high. When the biasing voltage is more than the knee voltage the potential barrier is overcome and the current increases rapidly with an increase in forward voltage. When the diode is reverse biased, the reverse bias voltage produces a very small current of about a few microamperes which almost remains constant with bias. This small current is a reverse saturation current. |
- In the given figure, a diode D is connected to an external resistance R = 100 Ω and an emf of 3.5 V. If the barrier potential developed across the diode is 0.5 V, the current in the circuit will be:
(a) 40 mA
(b) 20 mA
(c) 35 mA
(d) 30 mA - In which of the following figures, the pn diode is reverse biased?
(a)
(b)
(c)
(d)
- Based on the V-I characteristics of the diode, we can classify the diode as:
(a) bilateral device
(b) ohmic device
(c) non-ohmic device
(d) passive element
OR
Two identical PN junctions can be connected in series by three different methods as shown in the figure. If the potential difference in the junctions is the same, then the correct connections will be:
(a) in the circuits (1) and (2)
(b) in the circuits (2) and (3)
(c) in the circuits (1) and (3)
(d) only in the circuit (1) 
The V-I characteristic of a diode is shown in the figure. The ratio of the resistance of the diode at I = 15 mA to the resistance at V = -10 V is
(a) 100
(b) 106
(c) 10
(d) 10-6
An ideal PN junction diode offers ______.
Choose the correct circuit which can achieve the bridge balance.
