## Chapter Objectives and Summaries

### 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
AV=VOut/VIn
• 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.