Glossary of Terms
This page includes a glossary of terms simply click on the term to see its description
A component or part thereof that improves or changes a item but is not essential for its operation
A signal voltage or current that is variable.
Baseboards– the frame or construction on which the Model railway is built. this can be open frame, plywood or even foam.
(lamp or indicator) an incandescent means of light from electrical energy.
Cab Control
A system of electrical wiring that allows trains to be controlled by any one of a number of controllers while changing sections of track
Chip or Micro Chip
No not the sort in a microwave (sorry to disappoint) these magical fellows used to be known as integrated Circuits these are semiconductors that contain thousands in some cases millions of transistors and logic in a micro miniature housing (They are really mind-blowing devices and we will explain more later)
A device used for short term storage of electrical charge
Digital Command Control a system for control of Model railways using a type of data highway superimposed on a voltage that permits multiple trains to operate on the same section of track as well as a number of other functions and accessories.
Circuit Breaker
A device that automatically Breaks the circuit to prevent damage to the wiring or potential fire. (can be magnetically or thermally operated)
The device or PCB circuit that receives, reads and acts on the electrical signals sent from the controller of a DCC system
Semiconductor device that only allows electrical current flow in one direction (these are used in rectifiers in a group of four in a certain configuration)
A signal that is either at a high or low or zero or one usually +5v or Zero volts (on large control systems on commercial machines it can be zero or +24v.
An abbreviation of Double Pole Double Throw it describes a type of switch that operates two separate contacts from one position to another the switch can be fixed or momentary operation.
Usually refers to a wire that connects the track or accessory to a central bus wire arrangement
Usually refers to the power feed to the layout
A component that thermally protects the wiring of a system by self-destruction. (they cannot be reused)
LED ( Light Emitting Diode)
A Diode (see above) or semiconductor device that emits light when current is passed in the forward direction. Click here to visit our LED Calculator
Primary Cell
A non-rechargeable cell made of 2 dissimilar self-saccharifying materials separated by a dielectric often used to make up battery’s usually produces 1.2v to 1.4v per cell
Secondary Cell
A rechargeable cell made up of 2 dissimilar voltage reacting materials separated by a dielectric often used to make up battery’s usually produces 1.2v to 1.4v per cell
Sink & Source
Terms referring to a load or input e.g. sink current or source current sinking diagram

The circuits above show the use for digital circuits (such as decoders)

Toggle Switch
An electrical switch with a lever to operate wiping contacts
Electrical Units of Measurement
The following section provides definitions for units of electrical measurements and terms

Click on the term or measurement to open

Alternating Current is an electric current which reverses direction periodically. AC current is the way that electricity is distributed through the power network in the UK (Generally 50 cycles or Hertz)
This is the term used to describe the flow of electrical current, it is denoted by the letter A.
A or a = Amperes Ma = Milliamperes
Direct Current is an electric current that travels in only one direction, this is the type of current that a battery produces.
Farad a unit of measurement of electrical storage known as Capacitance
Symbol f or uf for microfarad
Hertz is the unit of Frequency e.g. the number of times an AC voltage changes its polarity in one second e.g. 50 Hz = 50 times per second
An Ohm is the electrical unit used for measuring resistance, its symbol is Ω.
The Watt is a unit of electrical power and is denoted by use of the letter W
KWH stands for Kilo watt Hour (how many thousands of watts are used in an hour)