Technical Engineering Definitions
"A" "B" "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M",
"N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"

"P" to Pd", "Pe" to "Pg", "Ph", "Pi" to "Pn",
"Po" to "Pot", "Pow" to "Pq", "Pr" to "Pt", "Pu" to "Pz"

Package type. A package type is a package which has the same case outline, varying only in size [as in a IC DIP Package], configuration, materials (including bonding, wire, or ribbon and die attach), piece parts (excluding preforms which differ only in size), and assembly processes. Package type examples include; IC Packages, or Transistor Packages, or Diode Packages.

Packet. A sequence of binary digits, including data and control signals, that is transmitted and switched as a composite whole, for data communications.

Packet Format. The structure of data, address, and control information in a packet.

Packet Switching. The process of routing and transferring data by means of addressed packets so that a channel is occupied during the transmission of the packet only, and upon completion of the transmission the channel is made available for the transfer of other traffic.

Pad. See Attenuator Pad, or PCB Pad, or Resistor Pad Schematics.

Pad Layout. The size, shape and spacing of the printed wiring board copper pads required for the mounting of a integrated circuit or component to the board.

Paired Cable. A term that refers to a cable that contains one or more twisted paired wires. A cable that contains wires that are twisted in pairs, but the wires pairs are not twisted with one another.

Paper Capacitor. A fixed capacitor that uses paper as a dielectric. The paper used in the capacitor is impregnated with oil or wax to remove any moisture. For more detail refer to the Dictionary of capacitor terms.

Parabolic Reflector. A paraboloid shaped reflector used in both the RF and Microwave frequencies. Refer to Dictionary of Radar terms, or Dictionary of Antenna terms.

Parallax Error. The error in meter readings that results when you look at a meter from some position other than directly in line with the pointer and meter face. A mirror mounted on the meter face aids in eliminating parallax error [graphic in side-bar]. Digital meters don't have this issue.

Parallel Circuit. Two or more electrical devices connected to the same pair of terminals so separate currents flow through each; electrons have more than one path to travel from the negative to the positive terminal.

Parallel RC Network
Parallel RC

Parallel Data. Some number of bits, such as a byte or word, transmitted over multiple lines at the same time.

Parallel-Negative Limiter. A resistor and diode, connected in series with the input signal, in which the output is taken across the diode and the negative alternation is eliminated.

Parallel Port. A port through which two or more data bits are passed simultaneously, such as all the bits of an 8-bit byte, and that requires as many input channels as the number of bits that are to be handled simultaneously. Centronics, IEEE-1284

Parallel-Positive Limiter. A resistor and diode connected in series with the input signal, in which the output is taken across the diode and the positive alternation is eliminated.

Parallel-Resonant Circuit. A resonant circuit in which the source voltage is connected across a parallel circuit (formed by a capacitor and an inductor) to furnish a high impedance to the frequency at which the circuit is resonant. Referred to as a tank circuit.

Hartley Oscillator Circuit

Parallel-to-Serial Converter. A component or circuit that receives parallel data [all bits of a word simultaneous] and outputs serial data [one bit of a word transmitted one after another]. Normally the serial portion needs to operate x times faster [8x faster with an 8 bit word] because only one bit is being transmitted at a time instead of the entire word. An IC example would be a Shift Register.

Parallel Tuned Circuit. A circuit which contains both a capacitor and inductor in parallel with each other [a resistor may or may not be included in the circuit].

Parametric Amplifier. A microwave amplifier which has its reactance varied with time.

Paraphase Amplifier. An amplifier that outputs two out of phase signals based on a single input.

Parasitic Capacitance. An unintended capacitance residing between pins of a component or conductors in a circuit. The circuit to the right shows the unwanted parasitic capacitance between the terminals of a transistor amplifier [in red]. Older texts may refer to parasitic capacitance as interelectrode capacitance, as the capacitance between electrodes or terminals of a device [used for tubes or transistors]. In general, parasitic capacitance changes the intended characteristics of a device or circuit, which than has to be compensated for. The example shows a few capacitors, but parasitic capacitance could exist between any nearby component or net in that circuit.

Parasitic Oscillation. An unwanted and unintended oscillation in a circuit due to stray or parasitic elements [stray capacitance and stray inductance].

Parity. A method of checking the accuracy of binary data. In binary-coded data, a condition that is maintained such that, in any permissible coded expression, the total number of 1s, or 0s, is always odd or always even. A binary digit appended to a group of digits or character so that there are an even number of 1s or 0s in the stream, or an odd number of 1s or 0s in the data field. Sometimes abbreviated as PAR. Related term; CRC Definition

Parity Bit. A bit appended to a data word to assist in the checking accuracy. A bit added to a binary code group intended to make the number of ones or zeros even or odd in that group.

Parity Check. The process of checking the accuracy of binary data, by counting the total number of 1s, or 0s, to insure that there is always an odd or always an even amount depending on the parity. Also refer to Parity Checker IC Schematic page showing an IC Parity checker.

Parity Error. A condition that occurs when the received number of 1s, or 0s do not equal the expected value. A signal output from a device that indicates the parity or number of 1s or 0s do not match the expected count. Sometimes abbreviated as PERR. For reference see manufacturers of Error correction ICs under the Components link below.

Part. One piece, or two or more pieces joined together, which are not normally subject to disassembly. See also End-Item. An item, such as an individual part or assembly, in its final or completed state. An element or component used in the production of electronic equipment or subsystem, such as a microcircuit, diode, transistor, capacitor, resistor, relay switch, or transformer.

Part Marking. How a component or device is mark with its part number, or some other identifying mark.

Pascal. A programming language. A unit of pressure [Pa].

Passband. The frequency range not attenuated by a filter. The portion of spectrum, between limiting frequencies.

Passivation. A chemical reaction that eliminates the detrimental effect of electrically reactive atoms on a semiconductor's surface.

Passive Component. A device that does not require a source of energy for its operation. List of Passive Components.

Passive Filter. A filter that does not use active components. Refer to the main entry on Passive Filters.

Passive Satellite. A satellite that reflects radio signals back to earth.

Passive Serial Interface. A term used with programming an FPGA. In the Passive Serial [PS] interface, an external host (configuration device, embedded processor, or host PC) controls configuration of the FPGA. Also called Passive Serial Mode, or Passive Serial Scheme; where Passive Serial may be Abbreviated as PS. Related terms include Active Serial Interface, and JTAG Interface.

Patch. A temporary circuit connection.

Patch Bay. An arrangement of Patch Panels.

Patch Cord. A cable used to connect two pieces of electrical equipment together.

Patch Panel. A Panel used to tie different circuitry together by means of Patch Cords, usually of the same or similar type, appearing on jacks for monitoring, interconnecting, and testing purposes. Patch Panels facilitate flexibility in the use, routing or restoration of a variety of circuit types. There are a number of standard patch panels; Bantam, 1/4" Longframe, Mini WECO, XLR Patchbays, Telecom Patchbays. Also called a Patch Bay, Although sometimes a patch panel is referred to as a part of a patch bay. Refer to the graphic, right. Patch Panel Recommendations.

Path Loss. The attenuation undergone by a signal between a transmitter and a receiver.

PC motherboard

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