SAFETY CHECKS IN SERVICING RADIO RECEIVER Preparation of work areas.
Working on power line and live circuits.
Range of electronic measuring instrument.
The teacher explains the dangers of dirty work areas and careless handling of live circuits, instruct students to always check the discharging of high voltage points, and explain the danger of working in a dark, and not well ventilated work areas, while students take notes on the danger of dirty work environment.
RESISTORS Graphic symbols of resistors.
Types, values, and ratings of resistors.
Carbon resistor color code.
The teacher uses charts to display the graphic symbols of various types of resistors, and determine their ratings, while students identify the resistors, and calculate their values from color codes.
RESISTORS/CAPACITORS Determine resistance value using color bands.
Comparison of meters and color values.
Graphic symbol for fixed and variable capacitors.
The teacher demonstrates how to use meter and determine resistor values, while the students compare the values of resistors from color codes, and multi-meter readings. The teacher draws the graphic symbol for fixed and variable capacitors, while the students identify the various types of capacitors.
CAPACITORS Types of capacitors.
Testing of capacitors.
The teacher demonstrate how to use multimeter to test capacitors, while the students identify the various types of capacitors.
DIODES Types of diodes, and their graphic symbols.
Testing for diodes (power, signal, LED and SCR).
The teacher provides various types of diode, and display chart showing the graphic symbols of diodes, demonstrate with multimeter how to determine the anode and cathode of a diode, and also it conditions, while the students identify different types of diodes provided by the teacher, and also practice how to determine the anode and cathode of a diode.
TRANSISTORS Graphic symbol of transistors (bipolar and uni-polar).
Differentiate types of transistors (signal, and power).
The teacher displays the chart showing the graphic symbol for bipolar, and unipolar transistors, and provides signal and power transistors, while the students sketches the symbol for bipolar and unipolar transistors from chart didplayed by the teacher.
Transistors configuration; CC, CE and CB
The teacher explains, and displays the chart showing the common, common emmiter, and common base transistor configuration. While the students sketches the CC, CE, and CB configuration from the displayed chart by the teacher.
BATTERY Graphic symbol of a symbol of a battery (multicell, single cell).
Different types of battery.
The teacher displays chart showing battery cell graphic symbol.
Provides different types of battery.
Test batteries, while the students sketch graphic symbol of battery cells, and identify different types of battery, and practice how to test them.
OHM’S LAW Defines ohm’s law, and explain relationship between resistance, voltage, and current.
Draw the symbol for ohm.
Relation between V,I,R.
The teacher defines ohm’s law, and explains the relationship between resistance, voltage and current, performs mathematical calculation on ohm’s law. While students observe as the teacher demonstrate connection of resistance in series and parallel.
OHM’S LAW Calculation of voltage and current (V=IR)
Resistors in series and parallel.
The teacher demonstrates connection of resistors in series and parallel.
Advantages of parallel connection.
The teacher demonstrates applications of parallel connection, while students take down notes.
Calculation of parallel and series resistors.
The teacher performs mathematical calculation on series and parallel connection, and use meter to measure the values. While the students observe the teacher measure resistance value with multimeter.
RADIO TV & ELECTRONICS
SS 2 SECOND TERM
Definition of electric power.
Measurement of electric power.
The teacher defines and explains electric power. He also solves problems relating to electric power.
The students solve problems relating to electric power.
ELECTRIC POWER. Power formula and its application (VI, I2/R, V2/R) .
Units of electric power.
Using the formula; VI, I2/R, V2/R, the teacher solves various problems of many levels, relating to power.
ALTERNATING AND DIRECT CURRENT. Definition of AC and DC.
Differences between AC and DC.
Uses of AC and DC in electric fan, electric grinding engine, blender.
The teacher defines and explains AC and DC. He also uses diagram to explain AC and DC. He should use multimeter to demonstrate how to measure AC and DC. The students use multimeter to measure AC and DC.
i. Definition of R.M.S values.
ii. Frequency and period of a sine wave.
Iii. Calculation of R.M.S values.
The teacher defines and explains R.M.S values, peak values, and frequency. Draws sine wave to show frequency and period. Work some examples on how to calculate R.M.S peak values and frequency. The students draw sine wave, and calculate R.M.S peak values.
The teacher displays and demonstrates the usage of the various measuring instruments.
The students observe the instruments, and practice how to use them.
ELECTRIC MEASURING INSTRUMENTS.
Basic circuit measurement of voltage, current, resistance in AC and DC circuits.
Ohmmeter for testing semi-conductor devices.
The teacher demonstrates how to use instruments in measuring current voltage and resistance in both AC and DC. He will show how to use multimeter to test diodes transistors etc, and also explains how to identify a faulty meter. The students observe and identify the various measuring instruments, and participate with the teacher in using measuring instruments to read the values of V,I,R.
POWER SUPPLY UNITS. Principles and operation of power supply units.
Power supply schematic diagram, showing stabilized low voltage DC power supply.
Rectification, half waves, full waves, and bridge.
The teacher explains the power supply unit using schematic diagram of a receiver circuit. He also explains the difference between half, full, and bridge rectifier.
The students identify the power supply units, and observe various components in the units.
POWER SUPPLY UNITS. Filtration.
Construction of a stabilized low DC power supply unit.
The teacher demonstrates the construction of a stabilized power supply unit, and explains the function of a regulator, or stabilizer in a power supply unit. The students observe the teacher’s demonstration , or practice the construction process.
Classes of amplifiers;- A,B,C, and AB amplifiers.
The teacher defines and explains the operation of the various classes of amplifier with the aid of a chart or sketch. He also shows the amplifier unit of a radio or TV set.
AMPLIFIERS. Construction ovarious classes of amplifiers.
Uses of the various classes of amplifiers.
The teacher uses cathode ray oscilloscope to display the frequency response of various classes of amplifiers, and construct s a signal power, or voltage amplifier. The students observe the frequency response of the various classes of amplifiers, and also construct a single stage signal or power amplifier.