Conventional Current

Definition: is when positive

charges flow from the positive

to negative terminal.

Definition: Electrical current is define as the rate of flow of electric charges.

SI unit : Ampere (A)

This 'topic' include

->1) Conventional current 3)Measuring current

->2) Electron flow 4)Effect of electrical current

Voltage/Potential different

Definition: Energy needed by a charge to move from one point to another in a circuit is known as potential difference or voltage.

1) SI unit: (V) (volts)

In series circuit

Vtotal

V2+V3=V1 OR Vtotal

Parallel Circuit

Potential differnce : V1 OR Vtotal=V2=V3

Vtotal

**C) VOLTAGE**

**D)RESISTANCE**

Definition: Resistance(R) of an electrical component is defined as the ratio of voltage across the component to the electrical current following through it .

SI unit : Ohm

Type of resistor

How resistance is affected in different circuit

Parallel

Series

Fix resistor

Rheostat

**Chapter 18:Electricity**

**B) Electrical Current**

**C) Voltage**

**D) Resistance**

A resistor having a definite resistance

value that cannot be adjusted.

An instrument used to control a current by varying the resistance.

Rtotal=R1+R2+R3+R4

V total/I total= V1/I1+V2/I2+V3/I3+V4/I4

/ = divide

Cannot sum the total resistance in a parallel circuit.

Rtotal = Vtotal/I total

**Voltage**

current

current

**A) Circuit**

-Definition: A series circuit is one that connects an electric source with its components one after the other, forming a single loop, providing only one path for the current to flow.

-Definition: A parallel circuit is one that splits into two or more branches, provide two or more different paths for the current to flow.

SERIES CIRCUIT

PARALLEL CIRCUIT

**A) CIRCUIT**

**Resistance =**

Electron flows

Measuring electric current with a ammeter

Ammeter MUST be connected

in series with the electrical

appliance ( in this case, the

light bulb) in order to get

the correct reading.

Effect of

electrical

current

Heating effect

Chemical effect (electroplating)

magnetic effect

Behavior of current,voltage and resistance

Circuit symbols

Power supply

Galvanometer

Wire

All these heating appliances contain

coils of high resistance wire

When electric charges move through a high resistance wire, some of the electrical energy is transferred to atoms in the wire

When the atom receive the energy, the atom vibrates more and the wire is heated up

application in real life

When temperature rises above the surrounding temperature, heats is given out

Special thanks to:

Michael

(c4science)

Special thanks to: MarshallBrain.com/science

**B)Electrical Current**

Definition: is when the electron flows from the negative terminal to the positive terminal

This 'topic' include: 1) Series circuit 3)measuring voltage

2) Parallel Circuit

Series

Parallel

Current

Voltage

Resistance

ITotal = I1 = I2 = I3

Current remain the same throughout

the series circuit.

Vtotal = V1 + V2 + V3

Voltage is split up into the electrical

appliances in the series circuit.

Rtotal = R1 + R2 + R3

Resistance is split up among all the

resistor in series circuit. (If we are

talking about the resistor's resistance)

Itotal = I1 + I2 + I3

Vtotal = V1 = V2 = V3

Vtotal

Itotal

Rtotal =

Current is split up into all the different branches in the parallel circuit.

Voltage remain the same throughout

the parallel circuit.

Special thanks to: Derek Owens

Electrical resistivity as a property of matter. The concept is explained, the equation is derived, and an example problem is solved.

Resistivity

R= resistance

P (rho) = resistivity

L= Length

A= Cross sectional area

Rho=resistivity of a material ,which means , how well a material resists or conduct an electric current.

Today topic will be on...

Electrical

current

Voltage

Circuit

Series

Circuit

Parallel

Circuit

Circuit

symbols

Conventional current

AND

Electron flow

How to

measure current?

Effect of

electrical current

Series

circuit

Parallel

circuit

How to

measure voltage?

ELECTRICITY

Measuring voltage

Today we will be covering...

CHAPTER 18

-Advantages: By adding more power source (like batteries) it can increase the output energy -> Higher voltage across the electrical appliances

-Disadvantages:It is impossible to control the electrical appliances individually.

-Advantages: If one of the electrical appliances blows, the circuit will still be a close circuit.

Disadvantages:

Having multiple power sources will not increase the voltage across the electrical appliances in the circuit.

The next concept is something out of our syllables...

You may not understand. :)

Voltmeter MUST be connected in parallel with the electrical appliance ( in this case, the light bulb) in order to get the correct reading.

voltmeter connected parallel to the light bulb

Notice something missing?

Resistance is missing!

To know what is resistance , you have to know voltage and current FIRST :)

Resistance

Type of resistor

How to calculate resistance

How resistance is affected in different circuits

A simple series circuit

If one of the bulb fuse, the circuit will break.

2 batteries

1 battery

Circuit 1 has more voltage across the lamp/bulb compare to circuit 2.

(taking that the batteries and the lamp/bulb are identical )

And

a simple parallel circuit

The brightness of the bulb will not be affected by the number of bulbs in the circuit.

Series circuit

Series circuit

Parallel circuit

Parallel circuit

or

Voltage :

When sum up the voltage across resistor 1 and 2 , it is equal to the voltage across the batteries.

resistor 1

resistor 2

the voltage is the same throughout the whole circuit. ( if the circuit is closed!)

Resistance

Sum all the resistance to find the total resistance. OR Find the individual resistance using R=V/I then sum them up.

when

resistance increase,

current decrease.

A short summery of the behavior of current, voltage and resistance :)

real life application for electroplating

Chemical effect (electrolysis)

Electrolysis is the process of passing electricity through the conducting solution to result in a chemical change

use to decompose compound into its constituent elements

Electrolysis of acidified water produces hydrogen and oxygen!

Resistor must be place in series with the electrical appliances!