what is voltage ?

The definition of voltage is the electromotive force or the electrical potential difference between two points in a circuit expressed in volts. Voltage is the potential energy that makes the electrical current flow in a circuit by pushing the electrons around. The easier way to understand voltage is to use a water analogy. Electricity flows through devices in either Direct Current (DC) or Alternating Current (AC). Voltage is a relative entity similar to energy. To be able to tell the voltage of a point, it must be compared to a reference voltage of another point. Voltages across parallel components in a circuit are equal. Voltage is symbolized by an uppercase italic letter V or E.

Voltage can be direct or alternating. A direct voltage maintains the same polarity at all times. in alternating voltage, the polarity reverses direction periodically. direct voltage is the potential difference between the terminals of an electrochemical cell. Alternating voltage exists between the terminals of a common utility outlet.