Knowledge Base

What is electronics
People First Experimented with electric current over 200 years ago and useful devices like light bulbs and electric motors have been in use for at least 100 years. There is nothing new about electricity! Electricity is probably the most useful form of energy because it can be turned into so many other kinds of energy (like sound, heat or light). As well as this, electricity is useful because it can be controlled.

What is an electronic System?

In electronics, a system is made up of individual circuits. These circuits are combined together so that they can do interesting and useful applications. Eventually the system produces an output. For example, MP3 players produce sound. The mp3 player is made up from lots of separate electronic units like a head phone, amplifier, battery, USB ect. The block diagram below shows a simple mp3 diagram.

Other Systems

There are many different types of systems. Some are simple, and others are complicated; like the internet system. Others are more simple; like Fire alarm systems and people counters. Every system can be understood, if you brake it down into simpler blocks and see how they work together.

Main parts of a system:

1 The input device (normally a transducer e.g. a microphone)

2 The output signal (normally a transducer e.g. a speaker)

3 The power supply provides the electrical energy to do all this.
Circuits:

For example an amplifier contains electronic circuits made up from electronic components. The diagram below shows an amplifier:

Circuits Digrams:

Circuit digrams are made of symbols which represent components. The diagram below shows a typical amplifier circuit. In order to understand electronics you must learn about components, how they work and their limitations.

Basic Principles of Electronics:

Electromotive Force (e.m.f)

A battery can provide an electromotive force or e.m.f. The diagram below shows this e.m.f which can drive an electric current around a circuit connected to the two ends of a battery. E.m.f is measured in volts (v). Other sources of e.m.f is the mains, dynamos and solar cells.

Potential Difference: (pd) Electric current can only flow between two points in a curcuit. The diagram below shows an example of p.d. In the curcuit below there is a p.d because the battery is producing an e.m.f potential difference.

Voltage:

In the circuit below there are two main points.

1 Positve volts (A battery has a Positve terminal)

2 Negative Volts (A battery has a negatve terminal)

To find the voltage, we measure the p.d between node A and node B. We use a tool called a voltmeter to measure p.d. If we want to measure the voltage across, say, a bulb, we connect it across node A and node B. (i.e in parallel).


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