1. Electronics
Speaker Project
Mr Sanders

2. Circuit Components
IC TBA 820M
The TBA820M is a monolithic integrated audio amplifier in a 8 lead dual in-line plastic package. It is intended for use as low frequency class B power amplifier with wide range of supply voltage: 3 to 16V, in portable radios, cassette recorders and
players etc.

3. Circuit Components
Resistors
Resistors determine the flow of current in an electrical circuit. Where there is high resistance then the flow of current is small, where the resistance is low the flow of current is large. Resistance, voltage and current are connected in an electrical circuit by Ohm’s Law.

4. Circuit Components
Capacitors
Capacitors are components that are used to store an electrical charge and are used in timer circuits. A capacitor may be used with a resistor to produce a timer. Sometimes capacitors are used to smooth a current in a circuit as they can prevent false triggering of other components such as relays.

5. Circuit Components
Switches
Some common switches are shown on this information sheet. Basically switches bring contacts together in different ways but they do the same switching job.
The Normal switch is common on many electrical devices. For example they are found on computer units for turning them on and off.

6. Circuit Components
LED (Light Emitting Diode)
Light Emitting Diodes (LED) are very rugged, they last a very long time and they are an optical source. (A LIGHT SOURCE) LEDs produce red, green, yellow, or orange light. Infrared LEDs are also available although light from this type cannot be seen by the human eye. These are used in security devices. LEDs are part of the diode family, consequently they must be connected the right way round or current will not pass through. They are usually protected by a resistor.

7. Circuit Components
Batteries
Batteries come in all shapes and sizes. They store electrical charge and as we all know when they are put into an electronic device such as a portable radio, they provide the power. The usual battery sizes are seen opposite. These are the type used in school projects and range from 1.5 volts to 9 volts.

8. Circuit Components
Speaker

9. Circuit Components
Using the information given in the previous slides, and the notes on your sheet..complete the following circuit diagram using the CIRCUIT SYMBOLS only where necessary.
1 – IC TBA
2 – Resistor
3 – Capacitors
4 – Battery
5 – Switch
6 – LED
7 - Speaker
The numbers will correspond to the component – you will then have to look back over your components sheet and draw in the CIRCUIT SYMBOL.

10. Circuit Components
Plenary
1 – What is an LED
2 – What does an LDR do?
3 – How hot does a soldering iron get?
4 – Name the 6 stages of soldering
5 – What is the purpose of a resistor?
6 – How do you tell how powerful a resistor is?
7 – Draw a circuit symbol for the resistor
8 – Draw the circuit symbol for an LED.