For a narrow base PNP BJT, the excess minority carrier concentration ($\triangle n_E$ for emitter,$\triangle p_B$ for base,$\triangle n_C$ for collector) normalized to equilibrium minority carrier concentration ($n_{E0}$ for emitter,$n_{B0}$ for base,$n_{C0}$ for collector) in the quasi-neutral emitter, base and collector regions are shown below. Which one of the following biasing modes is the transistor operating in?
In the figure shown, the npn transistor acts as a switch.
For the input V_{in}(t) as shown in figure, the transistor switches between the cut-off and saturation regions of operation, when T is large. Assume collector-to-emitter voltage at saturation V_{CE(sat)}=0.2V and base-to-emitter voltage V_{BE(sat)}=0.7V. The minimum value of the common-base current gain($\alpha$) of the transistor for the switching should be___________.
An npn bipolar junction transistor (BJT) is opening in the active region. If the reverse bias across the base-collection junction is increased, then
Consider an n-channel MOSFET having width W, length L, electron mobility in the channel µ_{n} and oxide capacitance per unit area C_{ox}. If gate-to-source voltage V_{GS} = 0.7 V, drain-to-source voltage V_{DS} = 0.1 V, (µ_{n} C_{ox}) = 100 µA/V^{2}, threshold voltage V_{TH} = 0.3 V and (W/ L) = 50, then the transconductance g_{m}(in mA/V) is_________.
A MOS capacitor is fabricated on p-type Si (Silicon) where the metal work function is 4.1 eV and election affinity of Si is 4.0 eV. E_{C }- E_{F}=0.9 eV, where E_{C} and E_{F} are the condition band minimum and the Fermi energy levels of Si, respectively. Oxide ${\in}_{r}=3.9,{\in}_{o}=8.85\times {10}^{-14}\mathrm{F}/cm$ , oxide thickness t_{ox}=0.1 µm and electronic charge q =1.6 × 10^{-19} C. If the measured flat band voltage of this capacitor is -1 V, then the magnitude of the fixed charge at the oxide-semiconductor interface, in nC/cm^{2}, is_________.
Two n-channel MOSFETs, T1 and T2, are identical in all respects except that the width of T2 is double that of T1. Both the transistors are biased in the saturation region of operation, but the gate overdrive voltage (V_{GS}-V_{TH}) of T2 is double that of T1, where V_{GS} and V_{TH} are the gate-to-source voltage and threshould voltage of the transistors, respectively. If the drain current and transconduction of T1 are I_{D1 }and g_{m}_{1} respectively, the corresponding values of these two parameters for T2 are
Assuming that transistors M_{1 }and M_{2} are identical and have a threshold voltage of 1 V, the state of transistors M_{1 }and M_{2} are respectively
In a MOSFET operating in the saturation region, the channel length modulation effect causes
The small-signal resistance (i.e., dV_{B}/dI_{D}) in k $\Omega $ offered by the n-channel MOSFET M shown in the figure below, at a bias point of V_{B} = 2 V is (device data for M: device transconductance parameter k_{N} = ${\mu}_{n}{C}_{\mathrm{o}x}^{\text{'}}(W/L)=40\mu A{V}^{2}$, threshold voltage V_{TN} = 1 V, and neglect body effect and channel length modulation effects)
The current i_{b} through the base of a silicon npn transistor is 1+0.1 cos(10000$\pi t$) mA. At 300 K, the r_{$\pi $} in the small signal model of the transistor is
The voltage gain ${A}_{V}$ of the circuit shown below is
In the circuit shown below, capacitors C_{1} and C_{2} are very large and are shorts at the input frequency. v_{i} is a small signal input. The gain magnitude |v_{o}/v_{i}| at 10Mrad/s is
For the BJT Q_{1} in the circuit shown below, $\beta =\infty ,$ V_{BEon} = 0.7v, V_{CEsat}=0.7v, The switch is initially closed. At time t = 0, the switch is opened. The time t at which Q_{1} leaves the active region is
In the silicon BJT circuit shown below, assume that the emitter area of transistor Q1 is half that of transistor Q2.
The value of current I_{0} is approximately
The amplifier circuit shown below uses a silicon transistor. The capacitors C_{c} and C_{E} can be assumed to be short at signal frequency and the effect of output resistance r_{0} can be ignored. If C_{E} is disconnected from the circuit, which one of the following statements is TRUE?
Consider the common emitter amplifier shown below with the following circuit parameters: β=100, g_{m}=0.3861 A/V, r_{0}=∞, r_{x}=259 Ω, R_{S}=1KΩ, R_{B}=93KΩ, R_{C}=250Ω, R_{L}=1kΩ , C_{1}=∞ and C_{2}=4.7μF.
The resistance seen by the source V_{s} is
The lower cut-off frequency due to C_{2} is
A small signal source ${v}_{i}\left(t\right)=A\mathrm{cos}20t+B\mathrm{sin}{10}^{6}t$ is applied to a transistor amplifier as shown below. The transistor has β = 150 and h_{ie} = 3kΩ. Which expression best approximates v_{o}(t)
In the following transistor circuit V_{BE} = 0.7V, r_{e} = 25mV / I_{E}, and $\beta $ and all the capacitances are very large
The value of DC current I_{E} is
The mid-band voltage gain of the amplifier is approximately
The DC current gain ($\beta $) of a BJT is 50. Assuming that the emitter injection efficiency is 0.995, the base transport factor is
For the BJT circuit shown, assume that the $\beta $ of the transistor is very large and V_{BE} = 0.7V. The mode of operation of the BJT is