Question 1

Draw the graph of current density versus electrical field in an intrinsic semiconductor and describe the mechanisms governing the three regions of this plot. Describe the construction of a photodiode with appropriate diagram. What is the minimum frequency (in Hertz) of the photons detectable by a ph

Accepted Answer

The behavior of current density versus electrical field in an intrinsic semiconductor reveals distinct mechanisms across different regions. Simultaneously, photodiodes, crucial optoelectronic devices, leverage semiconductor properties for light detection. Their construction involves a specially designed p-n junction, and their ability to detect photons is directly linked to the semiconductor's bandgap energy, determining the minimum frequency of light that can generate electron-hole pairs.

Question 2

Draw the structure of an n-channel JFET with appropriate voltage bias and explain the process of pinch-off. Explain the various regions on the drain characteristic of this JFET for VDS > 0 and VGS = 0V. Obtain the Q- point of a bipolar junction transistor in CE configuration with Ѵсс = 20 V, Ів = 10

Accepted Answer

Answer available — download the full PDF for complete details.

Question 3

Convert 396010 (decimal) into its hexadecimal equivalent and then divide it by hexadecimal number 0816. Express the result in octal equivalent. Obtain the expression for the output of the following logic circuit. Write its truth table. Which gate is represented by this circuit?

Accepted Answer

This response addresses the conversion of a decimal number to its hexadecimal and octal equivalents, along with performing hexadecimal division, as per sub-question (a). It also analyzes a common logic circuit, derives its Boolean expression, constructs its truth table, and identifies the gate represented by it, aligning with sub-question (b). The solutions leverage fundamental concepts of number systems and digital logic gates, which are core components of the BPHET-143 course curriculum.

Digi

Question 4

Write the truth table of a full adder and obtain the expressions of its Sum and Carry using the SOP method. Using the Boolean laws and theorems prove the following identities: i. (A + A) = 0 ii. (A+A)= A iii. A+(ABCD) = A iv. A•(ABCD) = A v. (A+B) (B+C) = AC + B. Draw the circuit of 2's complement b

Accepted Answer

Answer available — download the full PDF for complete details.

Question 5

In the universal biasing of a transistor, which resistor acts as a feedback element? How does it provide stability to the circuit? How class B amplifier is more efficient than class A amplifier? What will be the effect on the output of a push-pull amplifier if unmatched transistors are used? What ar

Accepted Answer

The universal biasing, also known as voltage divider biasing, is a highly stable method for setting the quiescent operating point (Q-point) of a BJT. It utilizes a feedback mechanism to maintain stability against variations in transistor parameters and temperature. Class B amplifiers offer improved efficiency over Class A by operating only during half of the input cycle, thus reducing power dissipation. However, their performance relies heavily on matched transistors, especially in push-pull con

Question 6

Why LC oscillators are preferred over RC oscillators to generate high frequencies? Why 2-stage amplifier is required in Wien bridge oscillator in contrast to a single stage amplifier in the phase shift oscillator? Draw the circuit of a Colpitts oscillator. Calculate its frequency of oscillation if v

Accepted Answer

The provided question covers fundamental concepts in Digital and Analog Circuits, specifically focusing on oscillators, rectifiers, and voltage regulators. Understanding the principles behind LC and RC oscillators, the design considerations for feedback networks, and the operation of power supply components like rectifiers and Zener regulators are crucial for BPHET-143. Each sub-question delves into a specific aspect, requiring both theoretical explanation and practical calculation. The design o

Question 7

You want to amplify a triangular wave signal of ± 10V amplitude and 10 MHz frequency. Which characteristic of op-amp will be significant in this case? What is its minimum value? Design and draw a circuit using an op-amp to get + 9 V at output for input less than +5 V and –9 V at output for input gre

Accepted Answer

This response comprehensively addresses the three sub-questions related to op-amp characteristics and circuit design, drawing upon fundamental principles of operational amplifiers as typically covered in the BPHET-143 course. It includes calculations for slew rate, a design for a comparator with specific output levels, and a multi-stage op-amp circuit for summing and differentiation, all while adhering to specified word limits and formatting requirements.

Question 8

Refer to Fig. 15.4 in your study material showing the geometry of the electron beam deflection in a CRT. In this CRT the length of deflection plates (L) is 3 cm and the distance between screen and centre of the deflection plates (R) is 12 cm. Accelerating voltage applied to the anode is 1200 V and a

Accepted Answer

This answer addresses two distinct aspects of electronics: the principles of electron beam deflection in a Cathode Ray Tube (CRT) and the design of an astable multivibrator using the versatile IC 555 timer. Part (a) involves calculations related to CRT deflection parameters, demonstrating how electron beam manipulation leads to a visible trace. Part (b) focuses on practical circuit design, detailing the selection of components for a 555 timer to produce a specific square wave frequency, which is

BPHET-143 Solved Assignment — January 2026 / July 2026

DIGITAL AND ANALOG CIRCUITS AND INSTRUMENTATION | IGNOU Bachelor of Science (General) (CBCS) (BSCG)

BPHET-143—January 2026 / July 2026

DIGITAL AND ANALOG CIRCUITS AND INSTRUMENTATION

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BPHET-143 Assignment Questions — January 2026

Q3. Convert 396010 (decimal) into its hexadecimal equivalent and then divide it by hexadecimal number 0816. Express the result in octal equivalent. Obtain the expression for the output of the following logic circuit. Write its truth table. Which gate is represented by this circuit?

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