Series Circuit Calculations 301

alternating current

AC. Electricity that reverses direction at regularly recurring intervals of time. Alternating current switches direction 60 times per second, or 60 hertz, in the U.S.

ammeter

A device used to measure current flow. An ammeter is connected in series to a circuit.

amperage

The strength of an electrical current. Amperage is measured in amperes (A).

ampere

A. A unit of measurement that describes both an amount of electricity and the time it takes to travel a certain distance. One ampere, or amp, equals one coulomb per second.

capacity

The amount of electricity that can safely flow through a circuit without it overheating. Capacity is an extremely important electrical quantity.

control

A component in a circuit that determines when and how electricity flows. Controls such as switches determine when a circuit is energized by opening and closing the circuit.

coulomb

C. The smallest quantity measurement of electrical current. One coulomb contains 6,250,000,000,000,000,000 electrons.

current

The flow of electricity. Current is measured in amperes (A).

DC

Direct current. Electricity that travels in one direction. DC does not reverse the direction of flow.

de-energized

A state at which stored energy in a system is removed. The power absent from a de-energized system may be electrical, mechanical, heat, hydraulic, or pneumatic energy.

direct current

DC. Electricity that travels in one direction. Direct current does not reverse the direction of flow.

directly proportional

A relationship in which one number increases or decreases at the same rate or ratio as another number. Directly proportional is the opposite of inversely proportional.

directly proportional

A relationship in which one number increases or decreases together with another number at the same ratio. Directly proportional is the opposite of inversely proportional.

electric shock

The flow of electricity through the body. Severe electric shock can be fatal.

electromotive force

EMF. The pressure that pushes electrons through a conductor. Electromotive force is also called voltage.

electrons

A negatively charged particle that orbits the nucleus of an atom. Electrons flowing between atoms causes electricity.

equations

A mathematical statement that shows the equality of two expressions. In 2 + 2 = 4, both sides of the equation are two different ways to express the same value.

formulas

A representation of a known equation using letters, numbers, and/or symbols. Formulas help electricians calculate electrical quantities and capacity.

fraction

A number that indicates parts of a whole number. Fractions appear as one number over the other with a slash or horizontal line between them.

inversely proportional

A relationship in which one number either increases as another decreases or decreases as another increases. Inversely proportional is the opposite of directly proportional.

joule

J. A unit of measurement for power. A circuit uses one joule when one volt forces one amp through a load for one second.

Kirchhoff’s Laws

Two laws that describe the flow of current in an electrical circuit. Kirchhoff's Laws indicate that what goes into a circuit must come out of it.

leads

A conductive device within a circuit to which other components can be attached. A lead has either a negative or positive charge.

load

A component in a circuit that converts electricity into light, heat, or mechanical motion. Examples of loads are a light bulb, appliance, or machine.

load

A component in a circuit that converts electricity into light, heat, or mechanical motion. Examples of loads include light bulbs, appliances, and machines.

meter

A device that measures electricity. Meters measure many different quantities, including voltage, amperage, and wattage.

multimeter

A device that combines the functions of an ammeter, a voltmeter, and an ohmmeter. A multimeter is the most versatile and common electrical measuring device.

ohm

Ω. A unit of measurement for electrical resistance. One ohm is required for one volt to produce one amp.

Ohm’s Law

The universal truth that describes the relationship between voltage, current, and resistance. Ohm's Law states that one volt equals one amp times one ohm.

ohmmeter

A device used to measure a circuit component's resistance. A component must be removed from a circuit to attach an ohmmeter.

parallel

An electrical route that has multiple loads and multiple paths. Parallel connections are used with voltmeters.

path

A conductor that directs electricity in a circuit. The path is often copper wire.

power

The rate at which a device converts electrical energy into another form, such as heat or light. Power is measured in watts (W).

power wheel

A round chart of equations used to calculate current, voltage, resistance, and power. The equations on the power wheel are derived from Ohm's Law and Watt's Law.

ratings

A classification that indicates an electrical device's capacity. Ratings are typically printed on devices and may indicate current, voltage, resistant, and/or power values.

resistance

The opposition to current flow. Resistance is measured in ohms (O).

resistance

The opposition to current flow. Resistance is measured in ohms (Ω).

resistor

A device used in circuits to limit current flow. Resistors can be used to prevent overheating.

schematic diagrams

An electrical print that uses symbols to represent all electrical components in a circuit. Schematic diagrams show the electrical relationships of all components, but not their physical locations.

series

An electrical route that may have multiple loads but has only one path. Series connections are used with ammeters.

series circuit

An electrical system that has only one path for the flow of electricity. Series circuits are limited because, for any load to work, every load in the circuit must be switched on.

short

The condition in which current takes a shorter, unintended path between two conductors. A short causes excess current flow.

source

A component that provides electrical power to a circuit. The source is the origin of electricity, such as a battery or power plant.

subscript

A letter, number, or symbol written or printed below the main line of text. Subscripts accompany electrical value abbreviations to indicate which specific components the values indicate.

troubleshooting

The systematic evaluation of the various components of a system, circuit, or process to locate a malfunctioning part. Troubleshooting a circuit often involves using electrical prints as a guide to find the problem area.

variables

A symbol, such as a letter of the alphabet, that represents an unknown quantity. In the equation x + 30 = 15, x is the variable.

volt

V. A unit used to measure electromotive force or pressure, which is called voltage. One volt of force is needed to cause one coulomb to do perform one watt of work.

voltage

A measure of electromotive force (EMF) or electrical pressure. Voltage is measured in volts (V).

voltage

A measure of electromotive force or pressure. Voltage is measured in volts (V).

voltage drop

A decrease in voltage that occurs as electricity passes through resistance. Voltage drops occur as voltage travels through a circuit.

voltmeter

A device used to measure voltage. A voltmeter is connected in parallel to a circuit.

watt

W. A unit of measurement for the wattage or power used or produced by a circuit. A circuit uses one watt when one volt forces one amp through a load.

Watt’s Law

The universal truth that describes the relationship between wattage, amperage, and voltage. Watt's Law states that one watt equals one amp times one volt.

wattage

The power used in a circuit. Wattage is measured in watts (W).

work

The result of electricity flowing through some type of resistance. Work appears in the form of heat, light, or motion.