POE Lesson 3-1 Key Terms

POE

Algorithm

A step-by-step procedure for solving a problem or accomplishing some end, especially by a computer.

Analog Signal

A signal having the characteristic of being continuous and changing smoothly over a given range, rather than switching suddenly between certain levels.

Analog to Digital

Conversion of an analog signal to a digital quantity such as binary.

Closed Loop System

A control system that considers the output of a system and makes adjustments based on that output.

Data

Information encoded in a digital form, which is usually stored in an assigned address of a data memory for later use by the processor.

Digital Signal

A system of discrete states: high or low, on or off, 1 or 0.

Digital to Analog

Conversion of a digital signal to its analog equivalent, such as a voltage.

Electromagnet

A conductor wrapped around an iron core. The two ends of the conductor are attached to a power source. When current passes through the conductor, the iron core becomes magnetized.

Feedback

The return to the input of a part of the output of a machine, system, or process (as for producing changes in an electronic circuit that improve performance or in an automatic control device that provide self-corrective action).

Flowchart

A diagram that shows step-by-step progression through a procedure or system especially using connecting lines and a set of conventional symbols.

Input

Information fed into a data processing system or computer.

Interface

The place at which independent and often unrelated systems meet and act on or communicate with each other.

Microprocessor

The central processing unit that is generally made from a single integrated circuit.

Normally Closed

The contact of a relay that is closed when the coil is de-energized.

Normally Open

The contact of a relay that is open when the coil is de-energized.

NTC Resistor

A negative temperature coefficient, also known as a thermistor, is a sensitive resistor whose primary function is to exhibit a change in electric resistance with a change in temperature.

Open Loop System

A control circuit in which the system output has no effect on the control.

Output

The information produced by a computer.

Photocell

A photo-sensitive resistor whose resistance decreases as the light striking the unit increases.

Polarity

The type of charge an atomic particle has.

Potentiometer

A switch that can provide variable motion control. It can vary the resistance within the switch, which affects both the current and voltage flowing out of the switch.

Programmable Logic Controller

A specialized heavy-duty computer system used for process control in factories, chemical plants, and warehouses. Closely associated with traditional relay logic. Also called a programmable controller (PC).

Reed Switch

An electromagnetically operated switching device.

Sensor

A device that responds to a physical stimulus (as heat, light, sound, pressure, magnetism, or a particular motion) and transmits a resulting impulse (as for measurement or operating a control).

Subroutine

A subordinate routine; specifically, a sequence of computer instructions for performing a specified task that can be used repeatedly.

Switch

A device for making, breaking, or changing the connections in an electrical circuit.

Transistor

A solid-state switching device.