A

Absolute Maximum Value – The value that should never be exceeded even momentarily.

Alternate – A repeated operation in which pressing a switch once turns it ON (or OFF) and pressing it again turns it OFF (or ON).

Alternate Action – An operation in which an internal mechanical lock mechanism holds the pushbutton in the operated state the first time when the pushbutton is pressed. And then the lock is released and the pushbutton returns to its original position the second time when it is pressed.

Alternative Operation – Operation in which the effective life of the motors is extended by alternating control of two motors. When one of the motors breaks down, operation can be maintained by the other one. An external switch is required.

Application Condition – The electrical and mechanical conditions under which the customer uses the device, including the current, voltage, load type, operating frequency, and operating speed.

B
Basic Switches – A Basic Switch is a small switch with a very small contact gap and snap-action mechanism and with a contact structure that switches for a specified movement and specified force enclosed in a case with an actuator provided on the exterior of the case.

C
Chameleon Lighting – Full illumination with one of three colors, red, green or orange which is obtained when light red and green at the same time.

City Water – Similar meaning to pure water but used in opposition to "wastewater." However, at water treatment plants "city water" may refer to water at a stage before it is purified so it has a broader meaning than pure water.

Clearance Distance – The minimum space distance between two charged parts.

Condensate – Condensed water from steam turbines or boilers.

Conductance – Conductance is a scale describing how easily current can flow. The relationship of conductance and resistance is defined by the following equation. Conductance = 1 ÷ resistance (W)

Conductivity – Unit of electrical conductance for liquids (Siemens: S). It is commonly expressed in micro-siemens (μS). It is the inverse value of electrical resistance, so the smaller it is, the higher the resistance, requiring a Level Controller with higher sensitivity.

Conduit Size – Conduit opening thread specifications.

Contact – The metal parts that touch when the movable plate reverses to perform electrical switching.

Contact Capacity of Output – The maximum load that can be switched by the 61F Level Controller.

Contact Rating – The rated voltage and current that can be applied to the contacts.

Contact Resistance – The resistance of the contact point of contacts. Generally, the contact resistance includes the conductive resistance of the spring and terminal section.

Contact Shape – The shape of the contacts. There are two shapes: rivet contacts and crossbar contacts.

Creepage Distance – The minimum distance on the surface of the insulator between two charged parts.

Crossbar Contact – Crossbar contacts are used for ensuring high contact reliability for switching micro loads.

D
Dielectric Strength – The voltage that can be endured when AC voltage is applied between discontinuous terminals, between each terminal and non-current-carrying metal parts, and between each terminal and ground. (The leakage current is specified separately.)

Digital Indicators – Devices that display a numeric value for an input signal. Digital Indicators are available in a wide variation of Single-digit Units and in Multi-digit Units (3 to 5 digits) with serial communications. Flexible Display are also available to provide various display capabilities. Digital Indicators help save work and space.

Distilled Water – Water that has been distilled by boiling and then recondensed from the vapors. Electrical resistance is not as high as pure water.

Distribution Reservoir – Water from the main water supply is distributed and temporarily stored in a reservoir for residential housing. These are used for separate small water supplies.

Dog – An operating object provided on the moving part of a machine to press or return the actuator of a limit switch.

Design Life – Expected length of time of acceptable performance under specified conditions.

DPDT basic switch – A basic switch with double-pole, double-throw contacts.

Drain – Water that is discharged to maintain a certain degree of purity in boiler water. The resistance of collected drain water is somewhat lower than normal water.

Drip-proof Switch – A switch with a sealing structure in which a rubber boot is incorporated in the plunger section and sealing material is applied between the case and cover. IP62 protection is achieved. A greater operating force is required.

Drive Frequency – Frequency that drives the sounding body.

E
Electric Corrosion – Corrosion that occurs with a conductive Level Controller. Conductive level controllers use the conductance of liquids to detect liquid levels. To achieve this, a small amount of current flows between the Electrodes. Ions in the Electrode are released to the liquid, leaving holes in the Electrode. These holes can cause Electrodes to break, damage the quality of the liquid, and cause pump failures.

Electrical Durability Curve – A curve that gives the change in durability for specific electrical usage conditions such as current, voltage, load, etc. in graph format. The durability depends on test conditions, so the data is for reference only.

Electrical Rating – The basic current, voltage, and load conditions used as a standard when using a Switch.

Elevated Water Tank – Water tanks that are installed on rooftops of high-rise buildings and apartments. They use the height of the tank (i.e., gravity) to supply water.

Enabling Hold Force – The force required for the held state.

External Stopper – A switch which sets the operating range of a thumbwheel switch arbitrarily from the outside. It is possible to change the setting by customer.

F
Force Necessary to Reverse the Direction of the Lever – The force required to move the actuator of a Fork Lever Lock Switch from the free position to the reverse operation position.

Forward Current – The current that flows to the LED.

Forward Voltage – The voltage at the ends of the LED.

G
Ground Terminal – A terminal which is connected electrically with the metal case of a limit switch.

H
Head – For a Limit Switch, a part with a mechanism that functions independently as the actuator.

Horizontal Side-by-side Mounting – Mounting Switches side-by-side with the long side of the Switches (rectangular models) facing sideways.

I
Idling Prevention – In high-rise buildings and apartments, water is pumped up from ground tanks to elevated tanks. If the ground tanks run out of water and the pump is still operating, the pumps starts pumping air and overheats the motors, potentially causing a burnout. To prevent this from happening, the pumps are stopped once the water drops below a certain level.

IF – The abbreviation for forward current.

Incandescent Lamp – A method to provide illumination with an incandescent lamp.

Indicator Lamps – An Indicator light which can signal different output conditions when supplied with a voltage.

Initial Operation Method – With this method, the internal relay operates when power is applied to the 61F Level Controller and resets when current flows between the electrodes. The wiring is the same as the sequential operation method.

Inrush Current – The instantaneous current that flows when the contacts close or a transitive current that is higher than the steady-state current.

Insulation Resistance – The resistance between discontinuous terminals, between each terminal and non-current-carrying metal parts, and between each terminal and ground.

Internal Stopper – A switch which sets the operating range of a thumbwheel switch internally at the factory. It is not possible to change the setting by customer.

J
JDEC – Abbreviation for Joint Electronic Device Engineering Council.

JFET – Abbreviation for Junction Field Effect Transistor. See also Field Effect Transistor.

Joint Electronic Device Engineering Council (JDEC) – A group within the Electronic Industries Association, originally formed in conjunction with NEMA. No longer affiliated with NEMA, the EIA group has retained the JDEC acronym.

Joule (J) – Unit of energy equal to one watt second. Written as 'joule'. Abbreviated to J.

Junction Field Effect Transistor (JFET) – A usually low power semiconductor (although high power SiC JFETs are being investigated) having a conductive channel whose resistance is controlled by the reverse voltage on the gate channel junction. See Field Effect Transistor.

L
LED Lamp – A method in which only the light source of an incandescent lamp model is changed from a filament to an LED and the LED is lit to provide illumination.

LED Lighting – A method in which an LED premounted to the PCB built into the Operation Unit is lit to provide illumination.

Limit Switches – A Built-in switch enclosed in a metal or resin case to protect it from external forces, water, oil, dust, dirt, etc.

Lock Travel Alternate – The distance or angle through which the pushbutton moves in going from the free position to the set position.

M
Magnet Blowout Basic Switch – A switch with a permanent magnet built into it to effectively suppress arcing in the contact mechanism. For direct-current switch.

Maintained-contact Switch – A switch with a reset button at the bottom of the switch case in addition to the plunger located on the opposite side of the reset button.

Manual Reset – To mechanically reset the Switch by manual operation.

Matrix Mounting – A method in which more than one Switch is mounted side-by-side horizontally or vertically.

Minimum Applicable Load – An operation in which a self-resetting Switch returns to its original position after being pressed and then released.

Movement until the Lever Reverses – The movement distance (or angle) to move the actuator of a Fork Lever Lock Switch from the free position to the reverse operation position.

Mutual Interference – Instability in the output that is caused by the effect of nearby sensors on each other.

N
Number of Notches – The number of positions or number of state changes that the selector or key can be switched to.

O
Operating Capacity – The electric capacity between the antenna and ground required to perform detection operations.

Operating Position Repeat Accuracy – The width of change in the operating position during repeated operation.

Operating Resistance (Level Switches) – The value of resistance between the Electrodes required for the 61F Level Controller to operate. The resistance must be lower than this value for the 61F to operate.

Operating Resistance (Limit Switches) – The resistance between the antenna and ground required to perform detection operations.

Operating Sensitivity – The electric capacity or the resistance between the antenna and ground required to perform detection operations.

Operating Voltage – The power supply voltage required for the 61F Level Controller to operate. For the 61F Level Controllers, it is at least 85% of rated voltage. Therefore the power supply voltage must not fall below 85% of rated voltage.

Operation Part – The position to operate an actuator. In case of rod actuators, the position is defined at the tip of a rod or the one third of whole length of the rod.

Output Current Capacity – The allowable current of an output circuit.

Overtravel – The distance or angle through which the actuator moves from the operating position to the total travel position.

P
PD – The abbreviation for permissible dispersion.

Permissible Dispersion – The amount of electric power that can be consumed.

Permissible Operating Force – The maximum load that can be applied to an actuator during operation.

Pull-out Strength of Cable – The maximum pull that a cable and the cable connection can withstand.

Pumped Water – Water that is pumped to another location. Most tap water is pumped through the water mains.

Pure Water – Water that has been purified for drinking, tap water available in an average household. Water in septic tanks is treated wastewater and should not be mixed with purified water.

Pushbutton Switches – A hand operated switch that performs input functions using open or closed contacts.

Push-lock, Turn-reset – An operation in which an internal mechanical lock mechanism holds the pushbutton in the pressed state when the pushbutton is pressed and the pushbutton returns to its original position when it is twisted to release the lock.

Push-pull Operation – An operation in which an internal mechanical lock mechanism holds the pushbutton in the operated state when the pushbutton is pressed and the pushbutton returns to its original position when it is pulled to release the lock.

R
Rainwater – Rain collected by rainwater pits. Electrical resistance is slightly higher than pure water.

Rated Frequency – The frequency of the applicable AC power supply.

Releasing Travel – The distance or angle through which the pushbutton moves in going from the returned position to the free position.

Reset Resistance – The value of resistance between the Electrodes required for the 61F Level Controller to reset. The resistance must be higher than this value for the 61F to reset.

Return Water – Water that circulates in a boiler as steam. It is the condensed water recovered from inside the pipes.

Reverse Voltage – The voltage limit when a reverse voltage is applied.

Rivet Contact – Rivet contacts are used in a wide application range from standard to high-capacity loads.

S
Self-holding – When the relay is triggered, the state is retained by a function called a self-holding circuit. For the 61F-GN Level Controller, electrode E2 is the self-holding circuit. A self-holding circuit enables a control range to be set and also prevents the relay from switching rapidly due to ripples on the liquid surface.

Separator – A device used to increase separation when the insulation distance may be insufficient or when there are metal components or copper wire nearby.

Septic Tank – Temporarily stores wastewater from toilets. The wastewater is treated to get rid of any solids before it discharges the fluid elsewhere.

Sequential Operation Method – Operation in which the internal relay switches when current flows between electrodes.

Set Position – The position of an alternate action pushbutton when it is in the self-held state, or the position or angle of a selector switch when it is in the self-held state.

Short-circuit Protective Device – A device, such as a fuse, that breaks the current to protect the Switch from short-circuiting.

Simultaneity – This term is used for switches that have more than one contact circuit. It indicates the difference in time or position between the contacts when all the contacts of the switch are opened or closed in one operation.

Spatter – The zinc powder produced when welding. Adhering spatter to the Limit Switch may cause malfunction of lever or lamp cover.

Specific Resistance – A liquid's resistance to current flow expressed in kΩcm. It has an inverse relationship with conductance. Electricity flows through the liquid between the Electrodes through an infinite number of paths. The specific resistance expresses the resistance to the flow of electricity.

Spring Water – Water that flows from spring wells. Similar to rainwater, the electrical resistance is slightly higher.

Storage Condition – Condition under which a Switch can be stored.

T
TE – Unit of width (usually) in a 19 inch rack. 1 TE = 1 HP = 0.2 inches = 5.08mm. See Useful Conversion Factors.

Technischer Uberwachungs-Verein (TUV) – Laboratories licensed by the German government for testing electronic products to DIN, IEC and VDE standards. http://www.tuv-uk.com/

Temperature Coefficient – The average percent change in output parameter (usually voltage) per degree Centigrade change in ambient temperature over a specified temperature range. (Expressed as %/°C). See also Ambient Temperature.

Temperature Derating – The amount by which power supply or component ratings are decreased to permit operating at elevated temperatures.

Temperature Effect – See Temperature Coefficient.

Temperature Range, Operating – See Operating Temperature Range.

Temperature Range, Storage – See Storage Temperature Range.

Tera – SI prefix multiplier. Multiplies by 1012. So 1 THz = 1 x 1012 Hz. Written as 'tera'. Abbreviated to 'T'.

Thermal Protection – Shuts down a power supply (PSU) if its internal temperature (or the temperature of specific components) exceeds a predetermined limit.

Thermal Runaway – A condition in a component where increasing temperature results in increasing losses bringing about a further temperature increase and so on. If left unprotected, this leads to failure.

Thermistor – A device which changes resistance with temperature. In power supplies, negative temperature coefficient thermistors frequently are used as inrush current limiting devices.

Three-Phase Electricity – Combination of three alternating currents having their voltages displaced by 120°, or 1/3 cycle. It is used for the distribution of high power electricity (all national electricity distribution networks distribute 3 phase electricity) and is particularly suited to high power loads.

Three Terminal Regulator – A voltage regulator in a standard 3 terminal transistor package.

Through Plated Hole – see Plated Through Hole.

Thyristor - A solid state device that has bistable electrical characteristics. Three common thyristor devices are diacs, Silicon-Controlled Rectifiers (SCR) and triacs.

Tolerance - Measured or specified percentage variation from nominal.

Top Hat Rail – See DIN Rail.

Toroid – A round magnetic core with a hole in the middle.

Total Regulation – The range of combined regulation tolerances such as the effects of input voltage variation, output load variation, temperature variation, drift and other specified variables. It is expressed as a plus/minus percent from nominal. Also called accuracy limit.

Tracking – A characteristic of a multiple-output power supply (PSU) that describes the changes in the voltage of one output with respect to changes in the voltage or load of another.

Tracking Over Voltage Protection (OVP) – A safety feature for power supplies with adjustable outputs where the trigger point of the OVP tracks with the voltage setting of the output such that a slow change in the output voltage will adjust the OVP setting but a fast change above the OVP point will trigger the OVP.

Transformer – Device which transfers energy from one circuit to another by electromagnetic induction. See Isolation Transformer, Step-Down Transformer, Step-Up Transformer.

Trifilar – Three conductors wound side by side on a magnetic core or bobbin in which all three conductors are wound in the same operation.

True Power – Actual power generated or consumed in a circuit.

Tuned Circuit – Circuit containing capacitance, inductance and (optionally) resistance, connected in series or parallel, which when energised at a specific frequency known as its resonant frequency, an interchange of energy occurs between the coil and the capacitor.

Turns Ratio – The number of turns on the transformer primary winding divided by the number of turns on the secondary winding. A Step-Down Transformer has a turns ratio more than one while a Step-up Transformer has a turns ratio of less than one. Usually explicitly specified as input/output turns ratio.

U
UL – Abbreviation for Underwriters Laboratories Incorporated.

UPS – Abbreviation for Uninterruptible Power Supply.

Undershoot – A transient change in output voltage outside of specified regulation limits. See Overshoot for a drawing to illustrate undershoot.

Under voltage Protection – A circuit that inhibits the power supply (PSU) when the output voltage falls below a specified minimum.

Underwriters Laboratories Incorporated (UL) – USA based safety agency. See http://www.ul.com/.

Uninterruptible Power Supply (UPS) – A type of power supply (PSU) designed to support the load for specified periods when the line varies outside specified limits. Generally, they are powered by ac (with battery operation taking over when the ac supply fails) and supply ac on their output. Most likely to be used to protect telecommunications equipment and computer systems.

V
Variable Resistor – See Potentiometer.

Varistor – Combination of Variable Resistor. A two-electrode semiconductor device having a non-linear, voltage-dependent resistance (usually a high resistance at low voltages and low resistance at high voltages). Often used to protect circuits against transient voltages.

Varnish Dip – The process of dipping a transformer or coil in varnish to bind or protect materials. Verband Deutscher Elektrotechniker (VDE) – German organisation charged to test and to evaluate products, including power sources. See http://www.vde.com/vde_en/.

Vias – See Plated Through Hole.

Volt (V) – Unit of measurement of electromotive force or potential difference. Symbol E, in electricity; symbol V in semiconductor circuits. A current of 1 A passing through a resistance of 1 ohm will produce a potential difference of 1 volt. See Ohm's Law. Written as 'volt'. Abbreviated to V.

Volt-Ampere (VA) – Unit of Apparent Power.

Volt Microsecond / Volts per Microsecond – Rate of change of voltage over a period of time expressed in volts/microseconds.

Volt Second – In a control circuit, the on-time x the voltage applied to the winding is controlled (effectively running the magnetic component at peak magnetic flux density).

Volt Second Clamp – A circuit in the control of the pulse width modulator located in the primary which terminates the pulse when the volt seconds applied to the primary of the transformer exceeds a predetermined value.

Voltage – A derivative electrical quantity, E, measured in the units volts and defined in terms of the independently obtained ampere, I, and the unit or Resistance, ohm (R) by Ohm’s Law E=IR.

Voltage Balance – The difference in magnitude, in percent, between differential tracking output voltages of a power supply (PSU) where the voltages have equal nominal values with opposite polarities.

Voltage Clamp – See Clamp Circuit

Voltage Dependent Resistor – Another name for Varistor.

Voltage Divider – Tapped or series resistance or impedance across a source voltage to produce a lower output voltage.

Voltage Drop – Difference in potential between two points in a passive component or circuit.

Voltage Limit – Maximum or minimum value in a voltage range.

Voltage Limiting – Bounding circuit used to set specified maximum or minimum voltage levels.

Voltage Regulation – The process of holding voltage constant between selected parameters, the extent of which is expressed as a percent. See also Regulation.

Voltage Source – A power source that delivers constant voltage.

Voltage Stabilization – The use of a circuit or device to hold an output voltage constant within given limits.

W
Warm-up Drift – The change in output voltage of a power supply from turn on until it reaches thermal equilibrium at specified operating conditions.

Warm-up Time – The time required after a power supply (PSU) is initially turned on before it operates according to specified performance limits.

Waste Electrical and Electronic Equipment Directive (WEEE) – The European Community Directive on waste electrical and electronic equipment which, together with the RoHS Directive, became European Law in February 2003. It sets targets for collection, recycling and recovery for electrical/electronic goods. The law puts the responsibility for these targets on the companies manufacturing electronic equipment. "Users of electrical and electronic equipment from private households should have the possibility of returning WEEE at least free of charge". Also, the manufacturers must use the collected waste in an ecologically friendly manner, either by ecological disposal or by reuse/refurbish. See also Restriction of Hazardous Substances Directive.

Watt (W) – Unit of measurement of Power. Written as 'watt'. Abbreviated to W.

Wide Range Input – The ability for a power supply to operate from a wide range of input voltages (110Vac and 230Vac and any voltage in between). A typical specification for wide range input would be 90Vac to 253Vac. Compare with Auto-Range Input.

Winding – A conductor wound onto a magnetic core, e.g., a transformer Primary Winding or Secondary Winding.

Working Voltage – The highest RMS value of the ac or dc voltage (disregarding transients) that may occur locally across any insulation at rated supply voltage.

X
X – Symbol for Reactance.

XC – Symbol for Capacitive Reactance.

XL – Symbol for Inductive Reactance.

X Capacitors – EMI filter capacitors across the line that meets the requirements of certain regulatory agencies.

Y
Y Capacitors – EMI filter capacitors between line and ground that meet the requirements of certain

Z
Z – Symbol for Impedance.

Zener Diode – A diode that permits current to flow both in the forward direction (like a conventional diode) and in reverse direction. When current flows in the reverse direction, Zener diodes are designed to drop a specified amount of voltage (the Zener Voltage). They are used primarily to regulate the output voltage of low power regulators.

Zener Voltage – The reverse voltage at which breakdown occurs in a Zener Diode.

Zepto – SI prefix multiplier. Multiplies by 10-21. So 100 zF = 100 x 10-21 F. Written as 'zepto'. Abbreviated to 'z'.

Zetta – SI prefix multiplier. Multiplies by 1021. So 100 ZF = 100 x 1021 F. Written as 'zetta'. Abbreviated to 'Z'.