BASIC CONCEPTS

Charge is an electrical property of the atomic particles of which matter consists, measured in coulombs (C).

Current is the time rate of change of charge, measured in Amperes (A).

• Direct Current (dc) is a current that remains constant with time.
• Alternating Current (ac) is a current that varies sinusoidally with time.

Two common types of current: Alternating Current (AC) and Direct Current (DC).

 

Voltage or Potential Difference is the energy required to move a unit charge through an element , measured in volts (V). 

Power is the time rate of expending or absorbing energy, measured in watts (W).

Circuit Elements is simply an interconnection of the elements.  

• Active element is capable of generating energy.
• Passive element absorbs energy.
• Voltage and current resources

Sources

• Ideal independent source is an active element that provides a specified voltage or current that is completely independent of another circuit elements.
• Ideal dependent source is an active element in which source quantity is controlled by another voltage or current.