Recent questions tagged class12

Which is doped heaviest in a transistor

asked Jan 28, 2014 by meena.p

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A change of 10 mA in the emitter current produces a change of 7.5 mA in collector current in a transistor . What should be change in base current to produce the same change in collector current.

asked Jan 28, 2014 by meena.p

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Find the value of $\tan({\frac{1}{2}}\sin^{-1}{\frac{1}{4}})$

asked Jan 28, 2014 by rvidyagovindarajan_1

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A transistor in common emitted mode the load resistance is $2k \Omega$ and the current gain $\beta =50,$ What is the power if input resistance is $500 \Omega$

asked Jan 28, 2014 by meena.p

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When negative voltage feedback is applied to an amplifier of gain 150, the overall gain falls to 15. Find the fraction of the output that is feedback to the input.

asked Jan 28, 2014 by meena.p

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In an amplifier, negative feedback is introduced with feedback fraction $\beta =0.01$. If voltage given with out negative feed back. is $2500$ what is voltage gain with negative feed back.

asked Jan 28, 2014 by meena.p

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In an n-p-n transistor only $3 \%$ of the charge carriers are allerved to recombine in the base region. The value of $ \alpha$ is

asked Jan 28, 2014 by meena.p

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What is the emitter current $I_E$ in a transfer where base current $I_B$ is $20 \mu A$ and $\beta =40$

asked Jan 28, 2014 by meena.p

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What is the output resistance, When we observe in a common emitter circuit the collector current increase from $9.5 \;mA\;to 10\;mA$ When the collector voltage increase from $2.5 \;to \;6v$ When base current is kept constant .

asked Jan 28, 2014 by meena.p

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In a common base amplifier current gain is $0.96$ and emitter current is $7.2\;mA$. The base current is

asked Jan 28, 2014 by meena.p

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In a common emitter transistor the current gain is 80. What is change in collector current , when change in base current is $250 \mu A$

asked Jan 28, 2014 by meena.p

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In the use of transistor as an amplifier $I_f \alpha =\large\frac{I_c}{I_e}$ and $\beta =\large\frac{I_c}{I_b}$ where $I_c$- collector current $I_b$- base current $I_e$- emitter current then

asked Jan 28, 2014 by meena.p

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In a transistor collector base is biased and emitter base is _ biased.

asked Jan 28, 2014 by meena.p

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An electron enters the p-n junction from the n-side with a velocity of $5 \times 10^5 m/s$ . If the depletion region is $5 \times 10^{-7} m/s$ wide and the potential barrier is $0.5 V$ What will be its speed When it enters P side ?

asked Jan 28, 2014 by meena.p

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An electron losely bound to the impurity of a doped semiconductor is able to jump to the conducting band because of thermal collision at temperature T k. If the impurity level is 15 mev below the conducting band, calculate the temperature.

asked Jan 28, 2014 by meena.p

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What is the resistivity of n-type semiconductors given: Density of conducting electrons $=8 \times 10^{13} /cc$; Density of holes $=5 \times 10^{12} /cc$ mobility of electron $=2.3 \times 10^4 cm^2 /v-s$ mobility of holes $=100 cm^2 /v-s$

asked Jan 28, 2014 by meena.p

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Find the current through resistance in the circuit.

asked Jan 28, 2014 by meena.p

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Let Potential at A and B be $V_A$ and $V_B$ respectively . In the given circuit. If the effective resistance is found to be $5 \Omega$ Then

asked Jan 28, 2014 by meena.p

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What is reading in ammeter $A_1$ and $A_2$ in given circuit.

asked Jan 27, 2014 by meena.p

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In the given diagram resistance of each diode in forward bias is zero and infinity in reverse bias . If a 2V battery is connected as shown in circuit What is the effective current.

asked Jan 27, 2014 by meena.p

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If $\ast$ is a binary operation on the set $(\{0, 1, 2, 3, 4, 5\})$ defined as \[ a \ast b = \left\{ \begin{array} {1 1} a+b, & \quad \text{ if a$+$b $<$ 6} \\ a+b-6, & \quad \text{ if a+b $\geq$ 6} \\ \end{array} \right. \] then draw the composition table for the operation and find the identity element and inverse of $4$ if exists.

asked Jan 27, 2014 by rvidyagovindarajan_1

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$\int\;\large\frac{a\sin x+6}{cos^2x}$$dx$

asked Jan 27, 2014 by priyakarthick05_1

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When a 10v battery is connected as shown in the circuit what is the potential difference across A and B ?

asked Jan 27, 2014 by meena.p

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The diode connected in forward bias has zero resistance and if connected in reverse biase has infinity resistance Find the effective resistance across A and B the given circuit.

asked Jan 27, 2014 by meena.p

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What is current and voltage across the diode in The given circuit given drift current is $ 2 \times 10^{-3}A$

asked Jan 27, 2014 by meena.p

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In a p-n junction hole with kinetic energy 250 mev approaches the junction from m-side . The potential barrier is 200 mev. What will be its kinetic energy when it crosses the junction .

asked Jan 27, 2014 by meena.p

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In Germanium it is found that concentration of conducting electron is $3 \times 10^{19} $ per cubic meter. When Phosphorus impurity is doped the concentration of conducting electron increases to $2 \times 10^{23}$ per cubic meter. If product of hole concentration and conducting electron is independent of amount of impurity find the hole concentration in doped Germanium.

asked Jan 27, 2014 by meena.p

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In the given circuit, potential barriers developed across diode is $0.5 v$ . Find the current in the circuit.

asked Jan 27, 2014 by meena.p

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Which of the following is reverse biased diode.

asked Jan 27, 2014 by meena.p

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In LEDs one can see emitted light to because

asked Jan 27, 2014 by meena.p

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Avalanche breakdown is due to

asked Jan 27, 2014 by meena.p

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Zener breakdown occurs:

asked Jan 27, 2014 by meena.p

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The approximate ratio of resistance in forward bias of p-n junction is

asked Jan 27, 2014 by meena.p

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The conduction band of a solid is partially filled at OK.Then the solid is

asked Jan 27, 2014 by meena.p

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Electrical conductivity of pure germanium can be increased by 1) increasing the temperature 2) doping with donor impurities 3) radiation with ultra violet rays. 4) doping with acceptor impurities

asked Jan 27, 2014 by meena.p

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In a p-n junction the depletion region is $200 nm$ wide and a electric field of $10^6 vm^{-1}$ exists in it. What is the minimum kinetic energy of conducting electron to diffuse through the barriers.

asked Jan 27, 2014 by meena.p

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In pure semiconductor number of conducting electrons is $5 \times 10^{20} $ per cubic meter. How many holes are there in $1 cm^3$ of the same semiconductor.

asked Jan 27, 2014 by meena.p

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The impurity atom with which pure silicon can be doped to make p-type semiconductors are

asked Jan 27, 2014 by meena.p

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What is intensity of electric field in the depletion region of which $2.5 \times 10^{-7} m$ if the potential barrier is $0.50 v$

asked Jan 27, 2014 by meena.p

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A p type semiconductor has acceptor level of 50 mev above the valance band. Find the maximum wave length of light which can create a hole.

asked Jan 27, 2014 by meena.p

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The diffusion current in p-n junction is due to

asked Jan 27, 2014 by meena.p

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Electronic conduction to in a semiconductor takes place due to

asked Jan 27, 2014 by meena.p

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Which of the following are incorrect statements about a transistor?

asked Jan 27, 2014 by meena.p

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The reverse bias in p-n junction

asked Jan 27, 2014 by meena.p

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In p-n junction diode : the depletion zone has

asked Jan 27, 2014 by meena.p

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Semi conductors doped with donor atoms have majority carriers as

asked Jan 27, 2014 by meena.p

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Fermi energy is

asked Jan 27, 2014 by meena.p

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Which of the following is true about semiconductors?

asked Jan 27, 2014 by meena.p

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A plate of thickness x made of refractive index $\mu $ is placed in front of one of the slits in a double slit experiment. What should be minimum thickness x . so that the central maxima turns to fringe with minimum intensity

asked Jan 24, 2014 by meena.p

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Equi convex lens is placed such that optic axis coincides with the x-axis, position of object is $(-40 \;cm, 1 \;cm) $ and position of image $(50 \;cm, -2\;cm) $ where is the lens located

asked Jan 24, 2014 by meena.p

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