Electronics Glossary · O

Electronics glossary — Letter O

68 definitions of electronic component and semiconductor terms starting with O. Part of the Hybrid Electronics glossary — an A–Z working reference for engineers and buyers.

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68 terms starting with O

obsolescence: The condition in which a component is no longer manufactured or supported. Managing obsolescence involves lifetime buys, approved alternates, redesign, or sourcing from excess and independent stock.
OCR: See optical character recognition.
O-crimp: An insulation support crimp for open barrel terminals (and contacts). Its crimped form resembles an “O” and conforms to the shape of the round wire insulation. O-crimp is also used to describe the circumferential crimps used on round, tubular ferrules.
octal: The octal number system has a radix (base) of 8, whereas the decimal system is to the base 10. The octal system, therefore, has eight distinct digits, namely 0, 1, 2, 3, 4, 5, 6, and 7. AMP has the capability of making switches which use octal code.
Octave: A frequency interval whose maximum value is twice the minimum value
Octave Band: A frequency interval whose maximum value is twice the minimum value
OD: Outside diameter.
OEM: original equipment manufacturer
Oersted: The unit of magnetic field strength (H) in the CGS system. One Oersted equals the magnetomotive force of one Gilbert per centimeter of flux path.
off-line memory: Any memory media capable of being stored remotely from the computer, which can be read by the computer when placed into a suitable reading device. For example, decks of punched cards, reels of magnetic tape, or disks.
Off-Line Power Supply: Power supply (linear or switching) that operates directly off the AC line. The input voltage is rectified and filtered prior to any isolation transformer.
offset current: An operational amplifier characteristic. The difference in current at the two inputs to bring the output voltage to zero.
Off-State Capacitance: Capacitance in the off-state measured at a specified frequency, amplitude, and DC bias.
Off-State Current: DC value of the current through a SiBar device that results from the application of the off-state voltage, VD. IDM designates the maximum off-state current.
Off-State Voltage: DC voltage when a SiBar device is in the off-state. VDM designates the maximum off-state voltage.
OFT: Optional Flame Test – Canadian Standards Associationâ€™s test for flameretardance. Tubing with an OFT rating is highly flameretardant.
ohm: The unit of measurement for electrical resistance. A circuit is said to have a resistance of one ohm when an applied emf of one volt causes a current of one ampere to flow.
Ohm’s Law: The law that relates voltage and current in a circuit. Ohm’s Law is:
ohms per square: A unit for measurement of resistor value by topological shape. It is based on the fact that the resistance of a square of resistor material is independent of the dimensions of the square. A resistor topology can be considered to be made up of contiguous squares. The value of the resistor is the product of the number of squares and the ohms per square.
olefin: Types of unsaturated aliphatic hydrocarbons, including ethylene, propylene, and butene. They are the bases for such plastics as polypropylene and polyethylene.
on-line memory: A memory media, with direct electrical interconnections, used as a nonremovable part of a computer system. For example, ROM ICs.
On-State Current: Current through a SiBar device in the on-state condition IT.
On-State Voltage: Voltage across a SiBar device in the on-state condition at a specified current, IT.
open barrel: The portion(s) of a terminal, splice, or contact that is crimped. When designed to receive the conductor, it is called the wire barrel. When designed to support or grip the insulation, it is called the insulation barrel. Wire and/or insulation barrels may be either “open” or “closed” in design. Closed barrels resemble a hollow cylinder into which the wire must be inserted. Open barrels are formed into an open “U” and are common to most strip terminals manufactured by AMP Incorporated.
Open Circuit Inductance (LO): The inductance measured at the winding of a transformer at a low flux density level.
open loop: Refers to operation of an amplifier without feedback, as opposed to closed loop which is operation with feedback.
Open Systems Interconnection(OSI): A 7-layer architecture model for communications systems developed by ISO and used as a reference model for most network architectures.
Open-Circuit Voltage: See No Load Voltage.
operand: One of the quantities entering into, or arising from, a computer operation. An operand may be an argument, a parameter, a result, or the location code for the next instruction.
Operate Time: The time interval between the coil energization (nominal coil voltage) and the closing of all normally open contacts. This includes time for the coil to build up its magnetic field (a significant limiting factor) and transfer time of the moveable contact between station-ary contact(s), and bounce time after the initial contact make. All Kilovac relays, except “AP” and “PD” power switching products include bounce time.
Operating Range Current: The range of normal operating currents in a circuit containing a PolySwitch device. Typically the hold current of the PolySwitch device should be greater than the top of the operating current range.
operating system: An organized collection of techniques and procedures for operating a computer. Specifically, a software package defined to simplify housekeeping and such routine chores as input/output, disk reading, and data conversion.
Operating Temperature: The maximum internal temperature at which a system, harness, or connector ay operate in continuous service; generally expressed as a time and temperature.
Operating Temperature Range: The specified temperature range over which a circuit or component is designed to operate without damage.
operating time: The time interval between satisfaction of the specified input conditions and the occurrence of the specified operation.
operational amplifier: op amp – Originally, an amplifier to perform mathematical operations. An amplifier with two differentially connected inputs, with high voltage gain, and with one output – which ideally is at zero volts when both inputs are at zero volts. It must also be capable of accepting negative feedback without oscillating.
optical character recognition: Automatic recognition of printed characters with a character reader. Commonly referred to by the abbreviation OCR.
optical fiber: Also called fiber-optic cable. A thin, flexible glass or plastic fiber capable of transmitting light over considerable distances by internal reflection.
optical transceiver: A module that converts electrical signals to optical signals and back for transmission over fiber, commonly in pluggable form factors such as SFP, QSFP and OSFP. Widely used in data center and telecom networks.
Optional Flame Test: OFT – Canadian Standards Associationâ€™s test for flameretardance. Tubing with an OFT rating is highly flameretardant.
OQPSK: Offset quadrature phase shift key modulation.
OR gate: A multiple-input gate circuit whose output is energized when any one or more of the inputs is in a prescribed state. Used in digital logic.
OSAT: Outsourced Semiconductor Assembly and Test – a company that packages and tests chips on behalf of foundries and fabless companies.
oscillator: (1) Any nonrotating device for setting up and maintaining oscillations of a frequency determined by the physical constants of the system. ( 2) A device for producing electric oscillations; specifically a radio-frequency or audio-frequency generator (especially of the nonrotating type).
OSS: operational support system
Outlet: Where the horizontal cabling terminates in the work area.
output: Information transferred from the internal storage of a computer to output devices or external storage.
Output Current Limiting: Feature that protects the converter (or load) from damage under overload conditions. The maximum converter output current is automatically limited to a predetermined safe value. If the converter is specified for auto restart, normal operatoin is automatically restored when overload condition is removed.
Output Filter: A low pass filter placed in the output of the rectified power converter to minimize (or smooth) the square wave or sine wave output of the converter. This filter has an LC,RC or Pi configuration.
Output Impedance: Ratio of change in output voltage to a change in output load current. Sometimes referred to as Dynamic Response.
Output Ripple and Noise: See Noise and Periodic and Random Distribution.
Output Voltage: Value of DC voltage measured at the output terminal of a converter.
Output Voltage Accuracy: Maximum allowable deviation of the DC output of a converter from its ideal or nominal value. Expressed as a percentage of output voltage. Often called output voltage tolerance
Output Voltage Range: Minimum and maximum output voltage limits within which a converter meets its operating specifications.
ovaled: A terminal (or contact) whose barrel has been made oval in shape to aid in placing two wires in the barrel.
Overcurrent Protection: Output monitoring circuit activated if the converter exceeds a preset current level.
Overload Protection: See Current Limiting and Foldback Current Limiting.
Overshoot: Transient change in output voltage that exceeds specified accuracy limits. Typically occurs on converter turn on/off or with a step change in output load or input line.
Overtemperature Protection: Design feature that protects the silicon die from exceeding its designed operating temperature range. The device will thermally cycle until the abnormal condition is corrected.
Overvoltage: Voltage for a circuit exceeds the allowable limit for that circuit. Can be transient or long-lasting.
Overvoltage Lockout: Design feature that protects the silicon die and downstream peripherals from supply voltage conditions that exceed its operating voltage limits. Raychem power switches have a nominal OVLO threshold of 6.4V.
Overvoltage Protection (OVP): Output monitoring circuit activated if a preset voltage level is exceeded. Depending on the type of circuit used, the OVP shuts the converter down, “crowbars” the faulty output or switches the converter to a different operating mode.
OVLO: Design feature that protects the silicon die and downstream peripherals from supply voltage conditions that exceed its operating voltage limits. Raychem power switches have a nominal OVLO threshold of 6.4V.
OXC: optical cross-connect
oxide: A compound of oxygen with one or more metallic elements. Rust is an oxide of iron.
Oxide Passivation: A layer of oxide, usually silicon dioxide either formed from the surface of a semiconductor die or deposited on the surface of a the die using chemical vapor deposition.
oxygen index: The minimum concentration of oxygen, expressed as volume percent, in a mixture of oxygen and nitrogen that will just support flaming combustion of plastic initially at room temperature.
ozone: An extremely reactive form of oxygen, normally occurring around electrical discharges. It is faintly blue and has the odor of weak chlorine. In sufficient concentrations, it can break down certain rubber insulations under tension (such as a bent cable).