Basic Electrical Circuit Materials

Colts Neck High School

Applied Technology

Conductance

The effectiveness of a conductor is measured in conductance.

The unit of measure for conductance is the siemens. (Ernst von Siemens)

G = I/R

G = conductance (in siemens)

R = is resistance (in ohms)

Conductors

Pathways that allow electrons to flow through an electric circuit.

Made from a variety of materials, usually metals. Copper, Aluminum, Brass, Silver

Conductor Size

Circular conductors are sized by the American Wire Gauge System. The larger the gauge number, the smaller the

cross-sectional area Circular Mils

A mil is equal to 1/1000th of an inchA circular mil is equal to the diameter of a

round conductor squared (D2)

Conductor Insulation

Insulators – materials with few free electrons, thus poor conductors of electrons.

Insulation – protective coating surrounding a conductor that prevents contact with other conductors and people.

Types of Conductors

Conductor Resistance

Cross-sectional area of a conductor The larger the surface area or diameter of a

conductor, the lower the resistance. Type of material

Different materials have different resistance values. Length of conductor

The longer the conductor, the greater the resistance. Temperature of material

Resistance of a material rises with the rising temperature.

Special Conductor Pathways

Breadboards – a device consisting of a piece of insulation material with a series of holes aligned in rows across it. Copper strips are run in parallel under it to provide pathways.

Special Conductor Pathways

Printed Circuit Board ( PCB) – A thin layer of conductor material, usually copper, cut into strips and attached to an insulated board.

Chassis – a metallic surface that serves as a part of the circuitry.

Example – the chassis of an automobile.

Special Conductor Pathways

Common Circuit Devices

Common circuit devices provide for a means of controlling the flow of electrons in an electronic or electric circuit. They also provide for safe operation. These include:Switches ConnectorsCircuit Protection Devices

Switches

Switches are categorized by their mechanical actuators, the part that causes it to open or close.

Simplest switch is a single-pole single-throw (SPST)

Circuit Protection Devices

Circuit protection devices include fuses and circuit breakers

Fuses are small glass tubes that contain wires that are engineered to burn if the current is too high.

Circuit Breakers are reusable safety devices that work on bi-metal actuators, or magnetism.

Connectors Connectors are used to

connect various components and conductors in an electronic or electric circuit. Many of them are solder less, some may require an additional crimping tool.

Resistors

Resistor – a component used to create desirable voltage drops and limit current values in electronic circuitry.

Various types exit such as composition resistor, chip resistor , potentiometers, and thermisters

Resistor Color Code Resistors have color coded bands that represent

the value, in Ohms, of the resister.