Electric circuits can be represented through circuit diagrams that show components like cells, batteries, switches, resistors, and meters. Current is the flow of electric charge through a conductor. It is measured in amperes and calculated as charge over time. Resistance opposes current flow and is calculated as potential difference over current based on Ohm's law, which relates current, voltage, and resistance. Power is the rate of energy transfer and is calculated as current times voltage. Fuses protect circuits by melting when there is too much current.

1. ELECTRIC CURRENT, POTENTIAL DIFFERENCE AND
RESISTANCE.

2. • Name.. M/Atif Stanikzai.
• Class.. 11th.
• Teacher Name.. ENAMULLAH MEHRABI.
• Subject.. Physics.
• Year.. 2023.
• Source… physics, Cambridge International AS and A level
And YouTube, Google.

3. CIRCUIT SYMBOLS AND DIAGRAMS.
• A circuit diagram is a graphical representation of an
electrical circuit.
• Circuit diagram are used for the Design,
construction and maintenance of electrical and
electronic equipment.

4. SOME IMPORTANT COMPONENT OF CIRCUIT DIAGRAM.
1. An Electrical Cell: It provides the source of current. In its symbol, the larger terminal is
positive, whereas the smaller one is the negative terminal.
2. A Battery: It is a combination of cells, and its utility is the same as the cell.
3. Switch: It is a plug key used to allow or stop the flow if current upon being pressed. It may be
an open or closed switch.
4. Wire joint: one device may be connected to the other using wires. This is shown by drawing
“blobs” at their point of connectivity.
5. Resistor: It is used to restrict the amount of current flow in the circuit.
6. Ammeter: It is used to measure the current passing at a particular point.
7. Voltmeter: It measures the voltage between two point in a circuit.

6. ELECTRIC CURRENT.
The net flow of charges through a point in one second is
called electric current.
• Its measured in amperes (A).
• So the formula of current is I=Q/t.
• For electric current, the electron should flow in one proper
direction.

7. CHARGE CARRIERS.
• Charge carriers are particles or holes that freely move within a
material and carry an electric charge. In most electric circuits and
electric devices, the charge carriers are negatively charged electrons
that move under the influence of a voltage to create an electric
current.

8. CURRENT AND CHARGE.
• The net flow of charges through a point in one second is called electric
current.
• In metal conductors the charged particles are free electrons. The
electrons are free to move from one ion to another and a net flow
of these electrons in one direction is an electric current.
• The equation of Current: Current= charge/time.
• The equation of Charge: Charge= Current*time.

9. EXAMPLE'S
• For Current: Calculate the current that gives a charge
flow of 180C in time of 38s.
• I= Qt… 180C38s= 4.73. I=4.73A.
• For Charge: I=0.60A and t=20s.
• Q=I*t= 0.60A*20s= 12. Q=12.

10. CHARGED PARTICLES.
• In physics, a charged particle is a particle with an electric charge. It
may be an ion, such as a molecule or atom with a surplus or deficit of
electrons relative to protons. It can also be an electron or a proton, or
another elementary particle, which are all believed to have the same
charge.
• Elementary charge e= 1.6*10-19C.

11. DERIVING I=NAVE?

12. VOLTAGE.
• Voltage describes the “pressure” that pushes electricity. The
amount of voltage is indicated by a unit known as the volt
(V), and higher voltages cause more electricity to flow to an
electronic device.
• The equation is: V=I*R.

13. RESISTANCE
• Resistance is the opposition that a substance offers to the
flow of electric current. It is represented by the uppercase
letter R. The standard unit of resistance is the ohm,
sometimes written out as a word, and sometimes
symbolized by the uppercase Greek letter omega Ω.
• The equation is: Resistance= potential differencecurrent.

14. • The potential difference: The energy difference between two
points in Electric field is called P.D.
• For example: like when we release a ball it accelerates
towards the ground. At height its high potential like the
energy is 30j, but on the ground its low potential
energy is 1j, So the potential difference is 29j.
• Electro motive force: is Defined as the total work done per
unit charge when charge flows round a complete circuit.

15. OHM’S LAW.
• Ohm’s law is a relationship between Voltage, current, and resistance.
• And Ohm’s law was developed by German physicist name Georg Ohm,
• And Ohm’s law has 3 formulas.
1. Voltage= Current*Resistance.
2. Current= VoltageResistance.
3. Resistance= VoltageCurrent.

16. ELECTRICAL POWER.
• E.P is the rate, per unit time, at which electrical energy is transferred
by an electrical circuit.
• The SI unit of power is the watt.
• General formula of power is P=VI.
• And electrical power is:
• POWER= energy transferred/time taken

17. FUSES.

19. POWER AND RESISTANCE.
• Power is the rate of doing work and resistance is a particle
that helps us to measure opposition to current flow in an
electrical circuit. In one of them, power is directly
proportional to resistance and in second, power is inversely
proportional to resistance.
• For resistance R, the power dissipated is given by,
• P= I(2)R OR P= V(2)/R.

20. CALCULATING ENERGY.
• Power= CURRENT*VOLTAGE,.
• ENRGAY= Power*time.
• Energy transferred= Current*Voltage*time.
• OR: W= IVT.

21. •THANKS