Advertisements
Advertisements
प्रश्न
Answer the following question.
Why photodiodes are required to operate in reverse bias? Explain.
Advertisements
उत्तर
The photodiode is reverse biased for operating in the photoconductive mode. As the photodiode is in reverse bias, the width of the depletion layer increases. This reduces the junction capacitance and thereby the response time. In effect, the reverse bias causes faster response times for the photodiode. The photocurrent is linearly proportional to the illuminance.
संबंधित प्रश्न
The graph shown in the figure represents a plot of current versus voltage for a given semiconductor. Identify the region, if any, over which the semiconductor has a negative resistance.
A plate current of 10 mA is obtained when 60 volts are applied across a diode tube. Assuming the Langmuir-Child relation \[i_p \infty V_p^{3/2}\] to hold, find the dynamic resistance rp in this operating condition.
With reference to a semiconductor diode, what is meant by:
(i) Forward bias
(ii) Reverse bias
(iii) Depletion region
Of the diodes shown in the following diagrams, which one is reverse biased?
A – pn junction has a depletion layer of thickness .of the order of
Use a transistor as an amplition
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.
 (a) |
 (b) |
- Name the type of a diode whose characteristics are shown in figure (A) and figure (B).
- What does the point P in figure (A) represent?
- What does the points P and Q in figure (B) represent?
Draw V-I characteristics of a p-n Junction diode.
Explain the formation of the barrier potential in a p-n junction.
