Advertisements
Advertisements
प्रश्न
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.
उत्तर
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
संबंधित प्रश्न
In the following diagram, is the junction diode forward biased or reverse biased ?
Plot a graph showing variation of current versus voltage for the material GaAs ?
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.
We use alloys for making standard resistors because they have ____________.
With reference to Semiconductor Physics,
Name the diode that emits spontaneous radiation when forward biased.
Avalanche breakdown is due to ______.
When an electric field is applied across a semiconductor ______.
- electrons move from lower energy level to higher energy level in the conduction band.
- electrons move from higher energy level to lower energy level in the conduction band.
- holes in the valence band move from higher energy level to lower energy level.
- holes in the valence band move from lower energy level to higher energy level.
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?
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 ______.
Describe briefly the following term:
breakdown voltage in reverse biasing
