Glossary of Electronics Terms

Actuator:
Object that causes the sensor to operate when detected.
Analog Output:
A continuously variable output quantity that represents an input.
Capacitive Proximity Sensor:
A device that detects the presence of metal and non-metal objects (wood, plastic,liquids, etc.) without physical contact.
CSA:
Canadian Standards Association, the agency for testing and approving products sold in Canada.
CENELEC:
European Committee for Electromechanical Standardization.
Complementary Output:
A sensor with two outputs, one output that is NO (normally open) and one output that is NC (normally closed). Similar to a SPDT (single pole double throw) switch.
Diffused Sensor:
A photoelectric sensor that contains the transmitter and receiver in the same housing. It uses the light reflected back from an object for detection. Used for short sensing ranges.
Flush Mounting:
Sensors that may be flush mounted in metal without being affected by surrounding metal and other sensors. Also known as shielded sensors. Sensors that may not be flush mounted have a larger electromagnetic field giving them a greater sensing distance for the same diameter, while making them sensitive to surrounding metals and other sensors. Also known as unshielded sensors.
Hysteresis:
The distance between the switching "on" point of the actuator approach and the switching "off" point of the actuator retreat. Its value is usually given as a percent of operating distance or a distance.
IEC:
The International Electrotechnical Commission which prepares safety and performance standards for electrical components.
Inductive Proximity Sensor:
A device that detects the presence of a metal object without physical contact.
Instant Contacts:
Relay contacts which energize or de-energize in conjunction with the input power switch or control device. These contacts operate independently of the timed contacts and can be used to control a separate function.
Interval Timer:
A delay which energizes an output for a set interval of time. The control switch or input power must be maintained during the timing interval to complete the delay. This timing function is also known as maintained interval delay, or interval ON.
IP Rating:
A rating system that defines the degree of protection provided by electrical enclosures according to IEC publications 144 and 529.
LED:
Light Emitting Diode used to indicate output.
Linear Output:
An analog output that is proportional to the input over a range.
Load:
A device that current flows through and has a voltage drop across it.
Motion Detector:
A device to detect zero, underspeed or overspeed conditions of pumps, conveyors, blower fans and other similar equipment which requires proper machine speed.
MOV:
Metal Oxide Varistor, a component which provides transient voltage protection.
Magnetic Effect Electronic Proximity Sensor:
Sensor that detects ferromagnetic actuators without contact.
Magnetic Sensor:
A device that is actuated by a magnet.
NAMUR Sensor:
A non-amplified sensor that supplies two different signal levels depending upon switch state. Consists essentially of an oscillator and is used to obtain low level signals which are able to drive a separate amplifier. Required in installation where special safety measures are necessary (locations with fire or explosion hazard).
NC (Normally Closed):
A switch output that is closed allowing current flow when an actuator is not present and open allowing no current flow when an actuator is present.
NO (Normally Open):
A switch output that is open allowing no current to flow when an actuator is not present and closed allowing current flow when an actuator is present.
NPN Output:
Transistor output that switches the common or negative voltage to the load. The load is connected between the positive supply and the output. Current flows from the load through the output to ground when switch output is on. Also known as current sinking.
Open Collector:
Refers to both NPN and PNP transistor devices with no components connected to the collector. When a load is connected to an open collector sensor it acts as a SPST (single pole single throw) switch.
Off Delay Timer:
A delayed de-energization of an output. The delay begins when the control is turned off. This timing function is also known as delay on break, delay on release, delay on de-energization or slow release.
On Delay Timer:
A delayed energization of an output. The delay begins when the control is turned on or power is applied to the input. This timing function is also known as a time delay, delay on make, delay on operate, delay on energization, or slow operate.
On Delay/Off Delay Timer:
This timing function is a combination of on delay and off delay.
One Cycle Timer:
A delayed energization of an output. The delay begins when the control is turned on or power is applied to the input. Output remains on either a fixed 0.8 seconds or a user set delay then resets.
Operating Distance:
The distance from the sensor that an actuator of Iron (Fe 37) of a specific size can be detected. Distance will decrease for other materials. Tests are carried out according to CENELEC EN 50010.
Operating Frequency:
The maximum number of on/off cycles that the device is capable of in one second.
Photoelectric Proximity Sensor:
A device that uses the properties of light sensitive elements to detect objects.
PNP Output:
Transistor output that switches the positive voltage to the load. The load is connected between output and common. Current flows from the device's output, through the load to ground when the switch output is on. Also known as current sourcing.
Power Control:
The control of a timing function through the application or removal of input power.
Power Drain:
The amount of current required to operate a sensor.
Power Supply:
The supply voltage range that sensor will operate at.
Proximity Sensor:
A device that detects the presence of an object without physical contact.
Range Tolerance:
Factory calibration of time range at room temperature and nominal input voltage.
Reflex Sensor:
A sensor that contains the transmitter and receiver in the same housing. Detection is made when an object interrupts the light beam between the sensor and the reflector. Used for medium sensing ranges. Also known as a retroreflective sensor.
Repeat Accuracy - Sensors:
The variation between any value of operating distance measures in an 8 hour period at a constant temperature and voltage.
Repeat Accuracy - Timers:
The maximum deviation in the time setting of a timer when operated under constant conditions (constant ON/OFF times, input voltage and temperature). The average of five consecutive operations, starting with the second operation, will serve as the reference for determining the maximum deviation.
Repeat Cycle Timer:
A timing function in which the output is alternately turned ON and OFF repeatedly as long as the control switch is closed or power remains applied to the input. This timing function is also known as a cycle timer or flasher.
Reset Time:
The minimum period of time the timer requires to prepare for a new cycle.
Reverse Polarity Protection:
Protection against damage to a sensor if connected to a power supply with incorrect polarity.
Ripple:
The ratio in percent between the residual AC voltage (ripple, peak to peak) on the DC voltage supply and the DC supply itself, that the sensor will operate on.
Self-Amplified Sensor:
Sensor whose output is amplified to a usable level.
Short Circuit Protection:
Protection against damage to a sensor if the load becomes shorted.
Switching Current:
The amount of current allowed to flow through the sensor without causing damage to the sensor. It is given as a maximum value.
Timing Variations vs. Temperature:
The timing change relative to a reference time delay at any temperature within specified limits. The reference time delay is based on five consecutive operations starting with the second operation and is measured at approximately 23?C, with constant ON/OFF times and input voltage.
Thrubeam:
A photoelectric sensor that requires two units, a transmitter and a receiver. Detection is made when an object interrupts the light beam between the transmitter and receiver. Used for long sensing ranges.
Tolerance:
The variation in a quantity from specified values or times.
Transient Protection:
Internal protection which prevents damage to the circuit from sudden changes in voltage.
Triac Output:
Output designed to control heavy AC inductive loads with high inrush and working currents (i.e., contactors, solenoids, valves, lamps). A built-in Triac controls the load.
UL:
Underwriter's Laboratories, Inc., the agency for testing and approving products sold in the United States.