Fundamental Principles of electrical engineering

Fundamental Principles of electrical engineering

1. Ohms law, power and energy

   • Ohms law: The current flowing into a circuit is directly proportional to the voltage as long as the temperature remains constant
     • Formula is V=IR
   • Power: The rate at which energy is used in a circuit over a period of time (A generator is a producer of power)
     • Formula is P=IV
   • Energy: The capacity for doing work
     • Formula is W=PT
     • Motors convert electrical energy into kinetic energy

2. Kirchoffs current and voltage laws

   • The current law states that at any junction the total current going into it must equal the current leaving
     • In simple : I1+ I2 = I3
   • The voltage law states that in any closed loop in a network, the algebraic sum of the voltage drops taken around the loop is equal to the resultant EMF acting in that loop.
     • In simple EMF=V1+V2+V3

3. Maximum power transfer theorem

   • This states that when a resistance of a load is equal to the internal resistance of the supply the power transfer from the supply to the load is at its maximum
     • In simple terms: When R=r the power transferred from the source to the load is at its maximum

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