LV03 Basic electrics and circuits

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Basic Automotive Electrics

What is electricity?

Electricity is the flow of electric charge, typically in the form of electrons, through a conductor. It is a fundamental force of nature and is crucial for our modern society. It powers our homes, businesses, and numerous electronic devices we depend on every day. Understanding the basics of electricity is essential in understanding how circuits work and how to create electrical systems.

​Every substance is made up of molecules.

All molecules are made up of atoms.

All atoms have an electrical charge.

What is Electricity?

Electricity starts at an atomic level. When electrons move from one atom to the next, current is produced.

Electrons are negatively charged.
Protons are positively charged.

The further away from the nucleus the electrons are, the weaker their bond.

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​How current is produced.

​Volts is electrical pressure
Amps is electrical flow
Resistance is a restriction to the current flow
Watts is electrical power

​Electrical units

​Voltage

​Voltage, also known as electric potential difference, is a measure of the force that pushes electric charges through a conduction path in an electrical circuit.

It is typically measured in volts (V) and represents the difference in electric potential between two points in a circuit.

In simple terms, voltage can be thought of as the pressure or strength of the electric current flowing through a circuit.

​Amps

​Amps, short for amperes, is the unit of measurement used to quantify the rate at which electric current flows in a circuit.

The higher the amperage in a circuit, the greater the rate of electric charge flow.

Too much current flow in a circuit will produce excessive heat which can lead to a fire.

Sometimes the letter I is used for amps. This stands for Intensity. It is derived from a French translation

​Resistance

​Resistance is expressed as R.

In an electrical circuit, resistance reduces the flow of current and converts some of the electrical energy into heat.

Resistors are used in circuits to control the flow of current, limit voltage, divide voltage, and perform various other functions.

The higher the resistance in a circuit, the lower the current that will flow through it for a given voltage.

​Watts, denoted by the symbol "W," is the unit of measurement used to quantify power in an electrical circuit.

It represents the rate at which electrical energy is consumed or produced. One watt is defined as one joule of energy per second.


Wattage is commonly used to express the power of electrical devices or systems, including light bulbs, kitchen appliances, and electronic equipment.

The wattage of a device is usually specified on its label or documentation and helps users understand how much energy the device consumes or produces.

​Watts

Voltage, amps and resistance are all linked and affect each other.


We can use simple calculations to work this out.

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​Ohms Law

Likewise, Watts, Amps and Volts are all linked and can be worked out using this calculation.

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​Watts triangle

Voltage, Amps and Ohms

​Name as many conductors and insulators as you can

​The difference between a conductor and an insulator is that a conductor allows the easy movement of electrons, and an insulator restricts the movement of electrons.

​Insulators

Replace this text with your body text.

​Duplicate this text as many times as you would like.

Conductors

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Glass, rubber, plastic, ceramic, wood, air, fibreglass, porcelain, quartz, and mica are all examples of electrical insulators.

Insulators

Copper, aluminium, silver, gold, iron, nickel, brass, bronze, carbon (in the form of graphite), platinum, zinc, tungsten, lead, tin, and mercury are all commonly used as electrical conductors.

​Conductors

Conductors and insulators

​What is a circuit?

A circuit is a complete path that allows electricity to flow. It consists of a power source (such as a battery or generator), conductive wires (usually made of copper), and components (such as resistors, switches, or light bulbs) connected in a closed loop. When the circuit is complete, electricity can flow continuously, creating a flow of electrons. Understanding the different types of circuits, such as series and parallel circuits, is vital for constructing and troubleshooting electrical systems.

Drag and Drop

What do we need to be able to build a basic automotive 12v circuit?​

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Placeholder

Drag these tiles and drop them in the correct blank above

Wire

Battery

Fuse

consumer

Switch

ECU

Transformer

Relay

Sensor

Ignition

Series circuits are those where the components are connected in series, forming a single path for electricity to flow. In series circuits, the total resistance increases as more components are added.

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​Series Circuits

Open Ended

What do you think happens if bulb 2 blows?

The fundamental rules for series circuits:

The amount of current is the same through any component in a series circuit.

​Components in a series circuit share the same current:

• I_total = I₁ = I₂ = . . . I_n

​Current:

​Voltage

Total voltage in a series circuit is equal to the sum of the individual voltage drops:

• V_total = V₁ + V₂ + . . . V_n

Labelling

Drag the correct voltages over the MM testing points. What voltage would you expect to see here?

Drag labels to their correct position on the image

12v

0v

4v

8v

​Resistance

When components (such as lamps) are added in series, the total resistance increases. The combined resistance is equal to the sum of individual resistances.

[ R = R1 + R2 + R3 + ....... ]

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• Current is consistent.

• Resistance accumulates.

• Voltage adds up.

​Remember

​In a series circuit

Parallel Circuits

​What is a Parallel Circuit?

A parallel circuit is a type of electrical circuit that contains multiple branches with components connected side by side.

Open Ended

What would happen if the first bulb blew?

There are three important rules to remember in a parallel circuit: the voltage across each branch is the same, the current divides, and the resistance decreases.

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​Rules of a parallel circuit

Work out your individual resistances first then divide 1 by the whole total.
This will give you the whole circuit resistance.

​We use the formula

Calculating resistance in a parallel circuit

Open Ended

What is this type of circuit?

Open Ended

What would happen if bulb 1 blew?

Open Ended

What would happen if bulb 3 blew?

Multiple Choice

Which of the following statements is true?

• Series circuits have a higher total resistance than parallel circuits.

• Parallel circuits have a higher total resistance than series circuits.

• Series circuits have a higher total current than parallel circuits.

• Parallel circuits have a higher total current than series circuits.

Open Ended

Using the calculation $$Rt=\frac{1}{\left(\frac{1}{R1}+\frac{1}{R2}+\frac{1}{R3}\cdot\cdot\cdot\cdot\right)}$$ What would be the total resistance if all the resistors were 4 Ω?

Open Ended

Calculate the total resistance of the circuit.

Multiple Choice

This is an example of a _______ circuit

• open
• series
• parallel
• square

Multiple Choice

This is an example of a ______ circuit

• Series
• Parallel
• Open
• Dihexihedral

Multiple Choice

The total resistance in this circuit is 

• 100 ohms
• 450 ohms
• 400 ohms
• 30 ohms

Multiple Choice

The total current through this circuit is

• 0.02 amps
• 0.09 amps
• 50 amps
• 9 amps

Multiple Choice

The voltage dropped across the 300 ohm resistor is 

• 6 V
• 9 V
• 2 V
• 30 V

Multiple Choice

As resistors are added in series to a circuit, the total resistance will...

• increase
• decrease
• stay the same

Multiple Choice

As the resistance of a circuit increases, the current will...

• increase
• decrease
• stay the same

Multiple Choice

In a parallel circuit which of the following is the same value throughout the circuit?

• Voltage
• Current
• Resistance
• Charge

Multiple Choice

The current going through the 45 ohm resistor is 

• 0.05 amps
• 0.2 amps
• 0.1 amps
• 5 amps

Multiple Choice

The total resistance of this circuit is 

• 25.7 ohms
• 315 ohms
• 324 ohms
• 90 ohms

Multiple Choice

The total current going through the battery of this circuit is

• 0.35 amps
• 0.0286 amps
• 0 amps
• 9 amps

Multiple Choice

A series circuit has how many pathways for the electrons to flow?

• Two
• One
• Many
• Zero

Multiple Choice

What is one problem with using a series circuit? 

• It has a lot of series. 
• If one light goes down, they all go down! 
• It doesn't work properly.
• There are no problems. 

Multiple Choice

What is a benefit of using a parallel circuit?  

• It gets confusing.
• There are no problems.
• If one light goes out, it does not affect the others. 
• If one light goes out, they all go out. 

Multiple Choice

An ammeter is a device that can be used to measure

• Current
• Voltage
• Resistance
• Power