Elenco Electronic Playground 50-in-1 Experiments - Manual (Page 6)

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INTRODUCTION TO BASIC COMPONENTS
Welcome to the exciting world of Electronics! Before
starting the first experiment, let’s learn about some of the
basic electronic components. Electricity is a flow of sub-
atomic (very, very, very, small) particles, called
electrons. The electrons move from atom to atom when
an electrical charge is applied across the material.
Electronics will be easier to understand if you think of the
flow of electricity through circuits as water flowing
through pipes (this will be referred to as the water pipe
analogy).
Wires: Wires can be thought of as large, smooth pipes
that allow water to pass through easily. Wires are made
of metals, usually copper, that offer very low resistance to
the flow of electricity. When wires from different parts of
a circuit connect accidentally we have a short circuit or
simply a short. You probably know from the movies that
this usually means trouble. You must always make sure
that the metal from different wires never touches except
at springs where the wires are connecting to each other
.
The electric current, expressed in amperes (A, named
after Andre Ampere who studied the relationship
between electricity and magnetism) or milliamps (mA,
1/1000 of an ampere), is a measure of how fast electrons
are flowing in a wire just as a water current describes
how fast water is flowing in a pipe.
The Battery: To make water flow through a pipe we need
a pump. To make electricity flow through wires we use a
battery or a generator to create an electrical charge
across the wires. A battery does this by using a chemical
reaction and has the advantage of being simple, small,
and portable. If you move a magnet near a wire then
electricity will flow in the wire. This is done in a generator.
The electric power companies have enormous
generators driven by steam or water pressure to produce
electricity for your home.
The voltage, expressed in volts (V, and named after
Alessandro Volta who invented the battery in 1800), is a
measure of how strong the electric charge from your
battery or generator is, similar to the water pressure.
Your Electronic Playground uses a 9V battery. Notice the
“+” and “–” signs on the battery. These indicate which
direction the battery will “pump” the electricity, similarly to
how a water pump can only pump water in one direction.
The 0V or “–” side of the battery is often referred to as
“ground”. Notice that just to the right of the battery
pictured below is a symbol, the same symbol you see
next to the battery holder. Engineers are not very good
at drawing pictures of their parts, so when engineers
draw pictures of their circuits they use symbols like this to
represent them. It also takes less time to draw and takes
up less space on the page. Note that wires are
represented simply by lines on the page.
The Switch: Since you don’t want to waste water when
you are not using it, you have a faucet or valve to turn the
water on and off. Similarly, you use a switch to turn the
electricity on and off in your circuit. A switch connects
(the “closed” or “on” position) or disconnects (the “open”
or “off” position) the wires in your circuit. As with the
battery, the switch is represented by a symbol, shown
below on the right.
Pipe
Wire
Water
Pump
Battery
Symbol for
Battery
(+)
9V
(–)
Valve
Switch
Symbol for Switch