Ch 3 Electrical Fundamentals

7/31/2019 Ch 3 Electrical Fundamentals

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Electrical Fundamentals

• What is electricity?

• How it is measured?

• What are the sources ofelectricity

• What does electricity will do?



What is electricity?

• Electricity is defined as the flow ofelectrons



• How can we get electrons to flow?

1. Source

2. Path



• Source: something that has an imbalanceof electrons and protons

– Protons are positively charged

– Electrons are negatively charged

– Since opposites attract, if we create animbalance of electrons and protons we have

electrical potential – Electrical potential is electrical pressure and it

is measured in volts



• Path: a conductor that connects theprotons with the electrons – A conductor is anything that has less than 4

electrons held loosely in their atom’s outer orbit

– This allows the electrons to move freely fromone atom to another

– An insulator holds its electrons in a tighterorbit and does not allow movement easily

– Once a path is established, electrons willmove because of the attraction caused by the

imbalance in the source



• How do we know electrons are moving?

• Can we hear, see or feel electronsmoving?

• We can only see the effects of electronsmoving

• Electrons if left unrestricted, will move sofast that extreme heat is created from thefriction generated by their movement



• Electricity: flow of electrons

• What is required for electrons to flow?

– A basic circuit• What is a basic circuit?

– Source

– Path – load



How is it measured?

• Volts: electrical pressure – Volts do not move through circuits

– Voltage is simply the strength of the

imbalance between protons and electrons andforce the electrons to move through aconductor

– Voltage is measured with a voltmeter that

measures the imbalance between the positiveside and negative side of a circuit

– Voltmeters must be wired in parallel



How is it measured?

• Amperes: the measurement of the amountof electrons flowing through the circuit – Amps are the measurement of current in an

electrical circuit – Amps are measured with an ammeter

– For an ammeter to measure current in acircuit, the current in the circuit must flow

through the ammeter – Ammeters must be hooked up to a circuit in

series



How is it measured?

• Ohms: a measurement of electronsresistance to flow through a circuit

– Resistance must be present in a circuit to

control the flow of electrons

– Resistance in a circuit can be measured withan ohmmeter

– An ohmmeter is self-powered and requiresthe circuit to be open



What are the sources of

electricity

• Chemical reaction: electrochemistry

• Magnetism: electromagnetism

• Pressure: piezoelectricity• Light: photoelectricity



































































































































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Ch 3 Electrical Fundamentals