Module 4 – Electronic Fundamentals

4.1 Semiconductors

4.1.1 Diodes

(a) Diode symbols;

Diode characteristics and properties;

Diodes in series and parallel;

Main characteristics and use of silicon controlled rectifiers (thyristors),

light emitting diode, photo conductive diode, varistor, rectifier diodes;

Functional testing of diodes.

(b) Materials, electron configuration, electrical properties;

P and N type materials: effects of impurities on conduction, majority and minority characters;

PN junction in a semiconductor, development of a potential across a PN junction in unbiased,

forward biased and reverse biased conditions;

Diode parameters: peak inverse voltage, maximum forward current,

temperature, frequency, leakage current, power dissipation;

Operation and function of diodes in the following circuits: clippers,

clampers,

full and half wave rectifiers, bridge rectifiers, voltage doublers and triplers;

Detailed operation and characteristics of the following devices: silicon controlled rectifier (thyristor),

light emitting diode, Schottky diode, photo conductive diode,

varactor diode, varistor, rectifier diodes, Zener diode.

4.1.2 Transistors

(a) Transistor symbols; 

Component description and orientation;

Transistor characteristics and properties

(b) Construction and operation of PNP and NPN transistors; 

Base, collector and emitter configurations;

Testing of transistors;

Basic appreciation of other transistor types and their uses;

Application of transistors: classes of amplifier (A, B, C);

Simple circuits including: bias, decoupling, feedback and stabilisation;

Multistage circuit principles: cascades, push-pull, oscillators,

multivibrators, flip-flop circuits.

4.1.3 Integrated Circuits

( a ) Description and operation of logic circuits and linear
circuits/operational amplifiers; 

(b) Description and operation of logic circuits and linear circuits;

Introduction to operation and function of an operational
amplifier used as: integrator, differentiator, voltage follower,
comparator;

Operation and amplifier stages connecting methods: resistive
capacitive, inductive (transformer), inductive resistive (IR), direct;

Advantages and disadvantages of positive and negative feedback.
4.2 Printed Circuit Boards Description and use of printed circuit boards.

4.3 Servomechanisms

(a) Understanding of the following terms: Open and closed loop systems, feedback, follow up, analogue transducers

Principles of operation and use of the following synchro
system components/features: resolvers, differential, control and
torque, trans-formers, inductance and capacitance transmitters;

(b) Understanding of the following terms: Open and closed loop, follow up, servomechanism, analogue, transducer, null, damping, feedback, deadband;

Construction operation and use of the following synchro
system components: resolvers, differential, control and torque,
E and I trans-formers, inductance transmitters, capacitance
transmitters, synchronous transmitters;

Servomechanism defects, reversal of synchro leads, hunting.