Electronic Engineering Glossary Terms

Object Code. The output from a complier.

Obsolete. Products that have been replaced by a newer or more advanced function. Products that have been discontinued or no longer being manufactured. Also refer to Part Life Cycle Definition, or Distributors of Obsolete Components.

Occupied Bandwidth. The width of a frequency band such that below the lower and above the upper frequency limits, the mean powers emitted are each equal to a specified percentage of the total mean power of a given emission [0.5%].

Octal Number System. A number system based on powers of eight. Refer to the Octal Conversion Table.

Octave. The interval between any two frequencies having a ratio of 2:1.

Octet. A byte of eight binary digits usually operated upon as an entity.

Odd Harmonic. A frequency that is an odd multiple of the fundamental frequency.

Odd Parity. A bit added to a binary code group which is used to make the number of ones or zeros in the group to be odd in number.

Off-Line. Pertaining to the operation of a functional unit when not under the direct control of the system with which it is associated.

Off-Line Test Equipment. Equipment that tests and isolates faults in modules or assemblies removed from systems.

Off-Set. An amount of DC voltage an AC voltage is riding on. The difference between the mid point of an AC voltage and zero volts.

Off-Set Null. A two terminal balance adjustment on an Op-Amp used to zero or null the output. A balanced condition of a circuit that represents zero output, as in Off-Set Null of an Op Amp. A related term; Null. Note the Off-set adjustment in the graphic, a 1K potentiometer connected between the two Balance terminals [BAL A and BAL B] of an Op-Amp.

Off-The-Shelf. Pertaining to equipment already manufactured and available for delivery from stock.

Ohm. The unit of electrical resistance. That value of electrical resistance through which a constant potential difference of 1 volt across the resistance will maintain a current flow of 1 ampere through the resistance.

Ohmic Value. Resistance in ohms. Also refer to Resistor Definitions Ohmmeter. A meter used to measure resistance. Ohmmeters normally also measure the reciprocal of resistance, in Mhos. An Ohm-meter is called a multimeter when it also measures current and voltage. Refer to the Test Equipment Manufacturers page.

Ohmmeter

Ohm's Law. The current in an electrical circuit is directly proportional to the electromotive force in the circuit. The most common form of the law is E = IR, where E is the electromotive force or voltage across the circuit, I is the current flowing in the circuit, and R is the resistance of the circuit.

Ohms per Square. The resistance of any square area of thin film resistive material as measured between two parallel sides.

Oilcan Tube. A type of planar tube, similar to the lighthouse tube, which has cooling fins. The oilcan tube is designed to handle large amounts of power at uhf frequencies.

Omnidirectional. Not directional, not following any one direction. As in Omnidirectional antenna [located in the Antenna definitions section of the site]. Equal sensitivity in all directions, and or equal outputs in all directions.

Ones Compliment. A ones compliment number is the compliment of all the binary digits in the binary number.

One Shot. Another name for a monostable multivibrator [see that listing]. A 74LS121 Monostable Multivibrator / 74LS122 Retriggerable One-Shot. A 74LS123 Dual Retriggerable One-Shot. A 4098 CMOS IC example. A 555 One Shot.

One Time Programmable. [OTP] A semiconductor device, such as a PROM or PLD, that may be user programmable only once, but once programmed the device may not be reprogrammed.