Unit 2: Analog Electronics (Lab: PHYDSC253P)
Table of Contents
1. Laboratory Objectives
The objective of this part is to provide students with hands-on knowledge and an overview of various instruments used in analog electronics. Students will learn to perform experiments related to semiconductor devices and report findings accurately.
2. PN Junction & Zener Diode Characteristics
These experiments involve studying the Volt-Ampere (V-I) relationship of semiconductor diodes.
- PN Junction Diode: Students plot the current against the voltage in both forward and reverse bias to understand the unilateral behavior.
- Zener Diode: The focus is on the reverse breakdown region to understand its role as a voltage regulator.
3. Solar Cell Analysis
The study includes plotting V-I and power curves for solar cells.
Goal: To find the maximum power point and calculate the overall efficiency of the solar cell.
4. Bipolar Junction Transistor (BJT) Characteristics
The characteristics of a BJT are studied in the Common Emitter (CE) configuration.
- Input Characteristics: Base current vs. Base-Emitter voltage for constant Collector-Emitter voltage.
- Output Characteristics: Collector current vs. Collector-Emitter voltage for constant Base current.
5. RC-coupled Transistor Amplifier
This practical involves designing and studying the performance of a single-stage amplifier.
- Design: Using voltage divider biasing to achieve a specified mid-gain.
- Frequency Response: Plotting gain against frequency to determine the bandwidth.
6. Operational Amplifier (Op-amp) Fundamentals
Students use IC-741 or IC-351 to design basic linear amplifier circuits.
- Inverting Amplifier: The output is out of phase with the input.
- Non-Inverting Amplifier: The output is in phase with the input.
Gain (Non-Inverting) = 1 + (Rf / Ri)
7. Op-amp Applications: Math Operations
Advanced experiments involve using the Op-amp to perform mathematical operations on electrical signals.
- Integrator: The output is the time integral of the input.
- Differentiator: The output is the derivative of the input.
- Adder/Subtractor: Combining multiple input signals into a single output.
Lab Exam Focus Corner
Frequently Asked Questions
- Why is voltage divider bias used for transistors?
It provides the best stability for the Q-point against variations in temperature and transistor parameters. - What is 'Knee Voltage' in a diode?
It is the forward voltage at which the current starts to increase rapidly.
Common Mistakes
- Biasing Polarity: Connecting the Zener diode in forward bias when trying to observe regulation. Remember, regulation occurs in reverse breakdown.
- Clipping: In Op-amp circuits, expecting a gain that results in an output voltage higher than the supply voltage (+Vcc / -Vee). The output will saturate.
Lab Tips
Tip: When plotting the frequency response of an amplifier, use semi-log graph paper (logarithmic scale for frequency) to clearly see the flat mid-band region and the roll-off at low and high frequencies.