GATE ECE 2026 | Bipolar Junction Transistor Question 1 | Analog Circuits

GATE ECE 2026

MCQ (Single Correct Answer)

-0.67

A small signal source, $V_i(t)=A \cos \left(10^5 t\right)+B \sin \left(10^7 t\right)$ is applied to a BJT circuit as shown in the Figure.

Assume zero source resistance, $V_{B E}=0.7 \mathrm{~V}, \beta_{\mathrm{dc}}=99$, Early voltage $=100 \mathrm{~V}$ and Thermal voltage $=25 \mathrm{mV}$. Effect of internal parasitic capacitances of the BJT may be neglected. Which expression is the best approximation of the output voltage $V_o(t)$ ?

GATE ECE 2026 Analog Circuits - Bipolar Junction Transistor Question 1 English

$-9.1\left[A \cos \left(10^5 t\right)+B \sin \left(10^7 t\right)\right]$

$9.1\left[A \cos \left(10^5 t\right)+B \sin \left(10^7 t\right)\right]$

$-190.4\left[A \cos \left(10^5 t\right)+B \sin \left(10^7 t\right)\right]$

$190.4\left[A \cos \left(10^5 t\right)-B \sin \left(10^7 t\right)\right]$

GATE ECE 2025

MCQ (Single Correct Answer)

-0.67

In the circuit shown, the identical transistors Q1 and Q2 are biased in the active region with $\beta=120$. The Zener diode is in the breakdown region with $V_Z=5 \mathrm{~V}$ and $I_Z=25 \mathrm{~mA}$. If $I_L=12 \mathrm{~mA}$ and $V_{E B 1}=V_{E B 2}=0.7 \mathrm{~V}$, then the values of $R_1$ and $R_2$ (in $\mathrm{k} \Omega$, rounded off to one decimal place) are ___________ , respectively. GATE ECE 2025 Analog Circuits - Bipolar Junction Transistor Question 5 English

GATE ECE 2025 Analog Circuits - Bipolar Junction Transistor Question 5 English

0.6 and 0.4

1.4 and 2.5

14.0 and 25.0

6.0 and 4.0

GATE ECE 2024

MCQ (More than One Correct Answer)

-0

Which of the following statements is/are true for a BJT with respect to its DC current gain $\beta$?

Under high-level injection condition in forward active mode, $\beta$ will decrease with increase in the magnitude of collector current.

Under low-level injection condition in forward active mode, where the current at the emitter-base junction is dominated by recombination-generation process, $\beta$ will decrease with increase in the magnitude of collector current.

$\beta$ will be lower when the BJT is in saturation region compared to when it is in active region.

A higher value of $\beta$ will lead to a lower value of the collector-to-emitter breakdown voltage.

GATE ECE 2020

MCQ (Single Correct Answer)

-0.67

The base of an $n p n$ BJT $T 1$ has a linear doping profile $N_B(x)$ as shown below. The base of another $n p n$ BJT $T 2$ has a uniform doping $N_B$ of $10^{17} \mathrm{~cm}^{-3}$. All other parameters are identical for both the devices. Assuming that the hole density profile is the same as that of doping, the common - emitter current gain of $T 2$ is