Notes on current electricity

1)Electrons in a static state have energy but they are most useful when they transfer their energy.
2)In order for current to flow the electrons should have a path to follow from negative to positive side of the power supply. This path is known as the circuit.

3)In DC (Direct Current) the current flow in one direction, from the power supply ,through the conductor, than the device that needs energy and than finally back to the power supply.

4)In AC(Alternating Current) the electrons can follow the path backwards and can reverse their direction. This could be done with the help of electric and magnetic forces.

5)The model of positive charge flow is known as the conventional current.

6)The energy delivered to the load (the device that uses energy and/or converts it) depends on the potential i-e the energy per charge and the rate at which the charge is delivered (the current).

7)A voltmeter is an instrument used to measure potential difference between any two points.
8)A voltemeter must be connected in parallel with a load in the circuit so that the potential is measured and compared equally before and after the load.
9)The voltmeter must have large resistance so that even if the conductor is poor to which the load is connected, the measurement by the voltmeter could divert the minimal current from the circuit.

10)In order to understand circuits better, we use symbols so that it is easier and convenient to understand.

11)There are many various devices that convert the electrical potential energy one source to various different forms. The original form can be chemical, mechanical, thermal or light energy.

12)Important equations for this unit:

   *Current is the rate of charge flow and is given the symbol "I". Current is the total amount of charge moving past a point in a conductor divided by the time taken. The formula is I=Q/T(Where I is the current in amperes (A), Q is the charge in coulombs (C) and t is the time in seconds)
   *The electrical potential energy for each coulomb of charge in a circuit is called the electrical potential energy. The formula isV=E/Q(Where V is the voltage, E is the energy required to increase the electrical potential of a charge Q)
   *The energy transferred by the charge flow is E=VIt(Where E is the energy in joules, V is the potential difference in volts, I is the current in amperes and t is the time in seconds)