Slide 1 : OHM’S LAW Presentation by
BYJA B
Current : Current
Electrons Flow in the Opposite way to the Conventional Current : Electrons Flow in the Opposite way to the Conventional Current We normally say that the current flows from positive to negative - + Electrons are negatively charged and therefore flow from negative to positive e-
Current : Current Current is the FLOW OF ELECTRONS AROUND A CIRCUIT
In metals, current is carried by electrons We use an ammeter to measure current The unit of current is the ampere (A)
Slide 5 : Ampere This is the scientist AMPERE.
He studied current in circuits and gave his name to the unit of current
In a series circuit the bulbs are all the same brightness : In a series circuit the bulbs are all the same brightness If the bulbs are of the same rating!
Current in a Series Circuit : Current in a Series Circuit 2A 2A 2A The Current in a Series Circuit is the Same at Every Point
Brightness of Bulbs in a Series Circuit : If a cell is added the current will increase and the bulb gets brighter Brightness of Bulbs in a Series Circuit
Brightness of Bulbs in a Series Circuit : If a bulb is added the current will decrease as there is greater resistance in the circuit and the bulbs get dimmer Brightness of Bulbs in a Series Circuit
Current in a Parallel Circuit : Current in a Parallel Circuit A PARALLEL circuit has more than one path for the current to flow through Bulb A Bulb B Assuming both bulbs are the Same…they will be the same brightness
Current in a Parallel Circuit : Current in a Parallel Circuit Bulb A Bulb B The Advantages of a parallel circuit are:
If one bulb fails ….the other will remain on
Both bulbs can be switched on separately
Current in a Parallel Circuit : Current in a Parallel Circuit The total flow of current is equal to the total current from all of the branches 2A 2A 2A 6A 6A
Voltage (Potential Difference) : Voltage (Potential Difference)
Voltage Is the Driving Force That Pushes the Current Around the Circuit : Voltage Is the Driving Force That Pushes the Current Around the Circuit We need Energy to push the electrons around the circuit.
In this case the energy comes from the lemon (in the form of chemical energy)
Slide 15 : Potential Difference/ Voltage This is VOLTA. He studied the driving force that pushes current around a circuit. He gave his name to the unit of Potential Difference The unit of Potential Difference is the VOLT (V)
Voltage in a Series Circuit : Voltage in a Series Circuit 12V 12V The voltage in a series circuit is shared across each component. The sum of the voltages across each component equals the source voltage 4V 4V 4V
What Is the Voltage? : What Is the Voltage? ?V 8V 8V 8V ?V
Voltage in a Parallel Circuit : Voltage in a Parallel Circuit 6V 6V 6V The voltage is the same across all components in parallel
Resistance : Resistance (Ohm’s law)
Resistance : Resistance It can be calculated using Ohm’s Law: Resistance is anything in a circuit that restricts the flow of current The unit of Resistance is the Ohm
Slide 21 : Current flows in a conductor when a potential difference is maintained across its ends.
In 1826, George Simon Ohm stated this law.
According to Ohm’s law, “the current flowing in a conductor is directly proportional to the potential difference across its ends provided physical conditions and temperature of the conductor remains constant”. If ‘V’ across the conductor is doubled, ‘I’ in it also get doubled.