Chapter Objectives and Summaries
for the Oxford University Press text by Walding, Rapkins and Rossiter:-
" NEW CENTURY Senior Physics - Concepts in Context "
CHAPTER 31 Designing Practical electronic circuits.
LEARNING OBJECTIVES
Knowledge of subject matter
- Define the quantities of measurement used for impedance
- State the formula for the resonant frequency of an RLC series circuit.
- Explain the construction of a typical DC power supply circuit.
- Recall appropriate practical applications of resistors, capacitors, and inductors.
- List the modes of operation of transistors in electronic circuits.
- Explain AC amplification using a class A common emitter amplifier with voltage divider bias.
- Explain the function of a digital gate and illustrate its truth table.
- Recognise digital IC circuits representing gates, multivibrators, clocks and counters.
Scientific Processes
- Interpret I/V curves and data tables to determine the nature of resistance or reactance at a given frequency.
- Communicate electronic information via an appropriate electronic circuit diagram.
- Generate analogies and represent graphically, the phase relationships between current, voltage and resistance for RLC series circuits.
- Design simple circuits to perform a given task or display information.
- Interpret signal input-output diagrams to determine a circuit's behaviour.
- Sketch variations in circuit designs to produce different outputs, such as frequency, for an IC based clock circuit.
- Locate and comprehend transistor and IC circuit information from text resources.
- Interpret circuit diagrams showing analog and digital ICs.
Complex Reasoning Processes
- Solve challenging problems using relationships between resistance, reactance, AC voltage and current including complex circuit analysis.
- Compare AC behaviour of R, L and C components including resonant circuits and their applications.
- Solve challenging problems involving AC amplification using transistor theory and circuits.
- Model complex electrical circuits with the use of block diagrams as an analysis tool.
- Select relevant knowledge and data to satisfactorily explain the operation of complex circuits.
- Illustrate creative thinking in the combination of digital gates to control or produce a given circuit outcome.
- Critically evaluate possible application circuits for devices, including fault finding or recognition of errors.
CHAPTER 31 SUMMARY
- Resistors, capacitors and inductors, through their property of AC reactance, can become the basis for electromagnetic resonant circuits or tuners.
- Impedance (Z) is the combined effect in any RLC circuit of resistance and capacitive or inductive reactance and represents a vector quantity. It is measured in ohms (*).
- Transistors may be used as direct current (DC) amplifiers, fast acting switches or as AC voltage amplifiers.
- AC voltage amplification may be produced with a transistor operating in a small signal, linear class A, common emitter configuration with voltage divider bias.
- AC voltage amplification in common emitter class A amplifiers is given by the formula
A_{V}=V_{Out}/V_{In}
- Linear integrated circuits include Op-Amps, Timers, Adders, Comparators, wave function generators and audio amplifiers.
- Digital integrated circuits include logic gates, multivibrators and counters.
- Logic circuits are networks of gates connected in sequential or combinational modes of operation.
- A multivibrator or Flip-Flop is the basic building block of sequential logic circuits and has its output state change from (0 to 1) or (1 to 0) when its input receives a pulse.
- A truth table represents the input-output characteristics of a logic gate. The simplest logic gate circuits are the AND, OR, NAND, NOR and NOT (inverter).
- Outputs of logic gates or combinations of gates can be represented by a Boolean algebra statement or equation.
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