Download Intro to Electronics

Technology 7
Mr. O’Rourke
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Electricity is a flow of sub-atomic (very, very
small) particles, called electrons.
Electrons move from a atom to atom when an
electrical charge is applied across the material.
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Wires: can be thought of as smooth pipes that
allow water to pass through easily.
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Usually made of copper, which offers low resistance
to the flow of electricity
Electric current, expressed in amperes is a measure of
how fast the current (or water) is flowing through the
wire (pipe).
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To make water flow through a pipe, we need a
pump. This is accomplished through the use of
a battery or other power source.
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Expressed in volts. A measure of how strong
the electric charge from your power source is.
+ or – indicate which direction electricity
(water) will flow.
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Similar to a faucet or valve, you use a switch to
turn the electricity off in your circuit.
A switch connects (closed or on) or disconnects
(open or off) the wires in your circuit.
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Why is the water pipe that goes to your kitchen
faucet smaller than the main supply line to
your house? Because you don’t need as much
water at that location.
Pipe size limits the water flow.
Similar to electricity, except that wires have so
little resistance, they would have to be super
thin (brittle) to limit the flow of electricity.
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Water flow through a large pipe could be
limited by clogging the pipe with an object
(rocks), which would slow the flow but not
stop it.
Resistors are like rocks, resistance is measured
in ohms.
Lower value resistor increases current
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Electrons are the particles that flow between
atoms as part of an electrical current.
A short circuit occurs when wires or
components from different parts of the circuit
accidentally connect.
A battery produces electricity using a chemical
reaction.
To decrease the current in a circuit you may
decrease the voltage or increase the resistance.
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Materials which have very high resistance are
called insulators, materials with very low
resistance are called conductors.
Adding resistors in parallel decreases
resistance, while adding resistors in series
increases resistance.
The electrical resistance of water decreases
when salt is dissolved in it.
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Capacitors are components that can store
voltage for periods of time.
Capacitors have low resistance to alternating
current and high resistance to direct current.
Adding capacitors in parallel increases the
capacitance while adding capacitors in series
decreases the capacitance.