Advertisements
Advertisements
Question
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.
Advertisements
Solution
As the semiconductors at room temperature act as insulators so they offer very high resistance value. But with the increase in temperature, they start conducting by decreasing the energy-gap and hence they offer less resistivity. So, the resistivity of semiconductors decreases with the increase in temperature and as a result resistance also decreases.
So to maintain the constant reading on the ammeter, we should increase the value of variable resistance R to compensate with the decreased value of resistance for semiconductor.
APPEARS IN
RELATED QUESTIONS
In the following diagram, is the junction diode forward biased or reverse biased ?
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.
We use alloys for making standard resistors because they have ____________.
Of the diodes shown in the following diagrams, which one is reverse biased?
The drift current in a p-n junction is from the ______.
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.
Draw V-I characteristics of a p-n Junction diode.
Explain the formation of the barrier potential in a p-n junction.
What is meant by forward biasing of a semiconductor diode?
