ENGINEERING TRIPOS PART IB - 2012/2013

PAPER 5 - ELECTRICAL ENGINEERING (1)

Linear Circuits and Devices

Leader: Dr. R. A. McMahon

Timing: Weeks 1-6 Michaelmas term

Structure: 10 lectures, 2 lectures/week weeks 1-4, 1 lecture/week weeks 5 and 6

AIMS

The aims of the course are to:

• Understand the operation of the bipolar transistor as a linear amplifier.
• Understand the principle of negative feedback and the effects of its application.
• Understand the concept and practical realization of an operational amplifier and be familiar with the use of operational amplifiers in feedback circuits.
• Appreciate the special considerations involved in output stages which are required to supply appreciable power.
• Understand how oscillators can be realized using linear circuits and other means

OBJECTIVES

As specific objectives students should:

Bipolar Transistor

• Know how to bias the device to a suitable operating point for linear amplification and how to construct a load line through the operating point.
• Be familiar with the small signal equivalent circuit for the bipolar transistor and be able to use it to determine gain, bandwidth and input and output impedances for the common emitter and emitter follower (common collector) circuit configurations.

Operational Amplifiers and Negative Feedback

• Know how to apply negative feedback and calculate the effects on gain, bandwidth and input and output impedances.
• Be able to analyse the long-tailed pair circuit and to understand its importance in practical operational amplifiers.
• Be able to relate the departures from ideality of practical operational amplifiers to the use of the long-tailed pair circuit.
• Know how to use operational amplifiers to make simple circuit elements, namely difference amplifiers, adders, integrators and differentiators.

Power Amplifiers

• Be able to set up a basic complementary emitter follower, or source follower, output stage.
• Know the conditions for class A, AB and B operation and the effect on efficiency and linearity.

Oscillators

• Be able to configure a simple oscillator using a linear amplifier and a feedback network.
• Understand how a hysteresis switch and a timing network can be used to make a relaxation oscillator.

SYLLABUS (Book References)

1. Bipolar Transistor - Device & Circuits (2L) (1) 76-83 (2) 368-375

• 1.1. Biassing & load lines. (1) 83-91 (2) 560-565
• 1.2. Small signal equivalent circuit. (1) 91-100 (2) 600-601
• 1.3. Emitter (source) follower. (1) 100-104, 60-62 (2) 642-644
• 1.4. Input & output impedance of CE and CC configurations. (1) 96-98, 100-104

2. Operational Amplifier Circuits (5L)

• 2.1. Revision of operational amplifiers (1) 114-128, 526 (2) 518-520
• 2.2. Negative feedback theory, gain = A/1+AB. (1) 164-181 (2) 636-641
• 2.3. Stabilisation of Gain, reducing distortion.
• 2.4. Improvement of bandwidth, input & output resistances.
• 2.5. Instability, AB = -1, positive feedback.
• 2.6. Voltage follower, adding, integrating & differentiating amplifiers. (1) 128-132 (2) 526-529
• 2.7. Input & output impedances with & without feedback. (1) 121-126 (2) 528-529
• 2.8. Common mode rejection ratio (long-tailed pair op-amp input stage). (1) 140-146 (2) 536-538
• 2.9. Input bias and offset currents, offset voltage, gain/bandwidth, slewing rate. (1) 146-151 (2) 528-539

3. Oscillators (1.5L)

• 3.1. Oscillators using linear circuits. (2) 574-576
• 3.2. Relaxation oscillators

4. Power Amplifier Stages (1.5L)

• 4.1. Emitter or source follower, power output and efficiency. (2) 574-576
• 4.2. Complementary transistor output stage.
• 4.3. Classes A, AB and B.

REFERENCES

Please see the Booklist for Part IB Courses for references for this module.

Last updated: May 2012