# Schedule

May29 - Jun 1 (20 periods)

# Content

- Electrostatics
- Current
- Potential difference
- Ohm's law
- Electric Power
- Electronics
- Digital electronics
- Electrical safety

# Instructional objectives

Students should be able to:

- Electrostatics:
- Describe simple experiments to show the production and detection of electrostatic charges
- State that charging a body involves the addition or removal of electrons
- State that charge is measured in coulombs
- State that the direction of an electric field at a point is the direction of the force on apositive charge at that point
- Describe an electric field as a region in which an electric charge experiences a force
- Describe simple field patterns, including the field around a point charge, the field around a charged conducting sphere and the field between two parallel plates (not including end effects)
- Give an account of charging by induction
- Distinguish between electrical conductors and insulators and give typical examples
- Recall and use a simple electron model to distinguish between conductors and insulators

- Current
- State that current is related to the flow of charge
- Use and describe the use of an ammeter, both analog and digital
- State that current in metals is due to a flow of electrons
- Show understanding that a current is a rate of flow of charge and recall and use the equation I = Q / t
- Distinguish between the direction of flow of electrons and conventional current

- Potential difference
- State that the e.m.f. of an electrical source of energy is measured in volts
- Show understanding that e.m.f. is defined in terms of energy supplied by a source in driving charge round a complete circuit
- State that the potential difference (p.d.) across a circuit component is measured in volts
- Use and describe the use of a voltmeter, both analogue and digital
- Recall that 1V is equivalent to 1 J/C

- Ohm's law
- Recall and use the equation R = V / I
- Describe an experiment to determine resistance using a voltmeter and an ammeter
- Relate (without calculation) the resistance of a wire to its length and to its diameter
- Sketch and explain the current-voltage characteristic of an ohmic resistor and a filament lamp
- Recall and use quantitatively the proportionality between resistance and length, and the inverse proportionality

between resistance and cross-sectional area of a wire

- Electric power:
- Recall and use the equations P = IV and E = IVt

Electronics:

* Draw and interpret circuit diagrams containing sources, switches, resistors (fixed and variable), heaters, thermistors, light-dependent resistors, lamps, diodes, ammeters, voltmeters, galvanometers, magnetising coils, transformers, bells, fuses and relays

* Describe the functioning of a capacitor

* Describe the action of a variable potential divider (potentiometer)

* Describe the action of thermistors and light dependent resistors and show understanding of their

use as input transducers

* Describe the action of a relay and show understanding of its use in switching circuits

* Describe the action of a diode and show understanding of its use as a rectifier

* Recognise and show understanding of circuits operating as light-sensitive switches and temperature-operated alarms (to include the use of a relay)

* Explain and use the terms analogue and digital in terms of continuous variation and high/low states

* Describe the action of NOT, AND, OR, NAND and NOR gates

* Recall and use the symbols for logic gates

* Design and understand simple digital circuits combining several logic gates

* Use truth tables to describe the action of individual gates and simple combinations of gates

# Teaching Process

- Start out with discussions on static electricity.
- Students build an electroscope
- Electronics is learnt by using the components to understand its behavior
- Some circuits are built by the students on the breadboard by the students.

# Activities

- Making an electroscope
- Making a Leyden jar
- Measuring resistance and resistivity
- Find out resistance, current and voltage in series and parallel circuits using the appropriate equations
- Build simple circuits
- Build a light sensitive switch using LDR and transistors
- Build a rectifier

# Suggested reading / References

- How we found out about electricity - Isaac Asimov

# Assignments / Evaluation

- Builing electroscope
- Building leyden jar
- Test