Voltage

Voltage , otherwise known as electrical potential difference or electric tension (denoted ∆ V and measured in units of electric potential volts, or joules per coulomb), is the electric potential difference between two points – or the difference in electric potential energy of a unit test charge transported between two points. Voltage is equal to the work which would have to be done, per unit charge, against a static electric field to move the charge between two points. A voltage may represent either a source of energy, (electromotive force), or it may represent lost, used, or stored energy (potential drop). A voltmeter can be used to measure the voltage (or potential difference) between two points in a system, usually a common reference potential such as the ground of the system is used as one of the points. Voltage can be caused by static electric fields, by electric current through a magnetic field, or a combination of all three.

VOLTAGE AND AMPERAGE

The strength of EMF or electrical potential is measured in units called volts. The more volts that are present, the greater the electrical potential will be. The voltage level of a dry cell battery will vary depending on how many surplus electrons there are at the negative terminal. A typical small dry cell battery has an EMF of 1.5 volts.

The greater the voltage in an electrical circuit, the greater the flow of electrons will be. Direct current is maintained by a constant or uninterrupted voltage.

Voltage is usually indicated with the abbreviation V. However, you may sometimes see  voltage abbreviated with the letter E, which stands for electromotive force. The  amount of electric      current flowing through a circuit is called amperage. The amount of current is measured in units called amperes or amps. One ampere of current is equal to the charge of 6,240,000,000,000,000,000  electrons flowing past a given point  in a circuit in one second. You can see that it takes many millions of electrons flowing in a   circuit to perform useful work!

In the electrical system, resistance to the flowing electrons (the amperage) can be decreased by using thicker conducting wires. Therefore, high-current circuits will use larger (thicker) conductors, while low-current circuits will use smaller (thinner) conductors.

Amperage is generally indicated with the letter A. However, you may also see amperage abbreviated with the letter I, which stands for intensity.