# Electricity 101 Voltage, Amperage, Wattage, and Resistance

Terms | Circuit Elements | Voltage

Amperage | Wattage | Resistance | Electricity Types | Electricity Sources

#### VOLTAGE

Voltage is the electrical force that moves electrons through a conductor.
Voltage is electrical pressure, also known as EMF (Electro Motive Force) that pushes electrons.
The greater the difference in electrical potential push (difference between positive and negative), the greater the voltage force potential.

**MEASUREMENT**

A VOLTMETER measures the voltage potential across or parallel to the circuit.
The Voltmeter measures the amount of electrical pressure difference between two points being measured. Voltage can exist between two points without electron flow.

**VOLTAGE UNITS**

Voltage is measured in units called VOLTS.
Voltage measurements can use different value prefixes such as millivolt (mV 0.001volts), volt (V), Kilovolt (kV 1,000 volts)

#### CURRENT (AMPERAGE)

CURRENT is the quantity or flow rate of electrons moving past a point within the circuit in one second. Current flow is also known as amperage, or amps for short. Higher voltage will produce higher current flow, and lower voltage will produce lower current flow. amperage could be compared to how quickly water is flowing from your bathroom faucet or garden hose.

**MEASUREMENT**

An AMMETER measures the quantity of current flow. Ammeters are placed in series (in line) to count the electrons passing through it, in much the same way as a water meter counts the gallons of water flowing through it.

**AMPERAGE UNITS**

Current flow is measured in units called Amperes or AMPS.
Amperage measurements can use different value prefixes, such as microampere (µA 0.000001), milliampere (mA 0.001), and Amp (A 1).

**AFFECTS OF CURRENT FLOW**

Two common effects of current flow are the generation of **Heat** and **Electromagnetism**.

**HEAT:**

When current flows, heat will be generated. The higher the current flow, the greater the heat generated. An example would be a light bulb. If enough current flows across the filament, it will glow white hot and illuminate to produce light.

**ELECTROMAGNETISM:**

When current flows, a small magnetic field is created. The higher the current flow, the stronger the magnetic field. An example: Electromagnetism principles are used in alternators, ignition systems, and other electronic devices.

#### WATTAGE

A watt is a unit of measurement applied to electrical power in terms of the amount of energy consumed. Watts can be calculated by multiplying the voltage times the amperage in a circuit. If we continue with the water comparison wattage would be like the volume of water required to fill your bathtub or brush your teeth.

#### RESISTANCE

Resistance is the force that reduces or stops the flow of electrons. It opposes voltage.
Higher resistance will decrease the flow of electrons and lower resistance will allow more electrons to flow.

**Infinite Resistance:**

so much resistance that current cannot flow through the circuit ("open circuit.")

**Zero Resistance:**

no resistance and current can flow through the circuit ("closed circuit")

**MEASUREMENT**

An OHMMETER measures the resistance of an electrical circuit or component. No voltage can be applied while the ohmmeter is connected, or damage to the meter will occur.

**Example:** Water flows through a garden hose, and someone steps on the hose. The greater the pressure placed on the hose, the greater the hose restriction and the less water flows.

**RESISTANCE UNITS**

Resistance is measured in units called OHMS.

Resistance measurements can use different value prefixes, such as Kilo ohm (K 1,000) and Megaohms (M 1,000,000).

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