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"

Pull-Down Resistor. A resistor tied to an input or output pin to tie the line to ground when not being driven.

Pull-In Frequency Range. The maximum frequency difference between the local oscillator or clock and the reference frequency of a phase-locked loop over which the local oscillator can be locked.

Pull Switch. A switch which is actuated by a device, such as a pull rod or a chain which requires pulling for each action.

Pull-Down Resistor. A resistor connected at the output of a device to hold the output low when not being driven, or located at the input of a component to insure a valid logic level with no input. A pull-down resistor is identical to a pull-up but not used with logic that would draw more current than forced low.

Pull-up Resistor. A resistor tied to Vcc to pull a line high when not being used. How to calculate a Pullup resistor.

Pulsating DC. A DC voltage that varies in amplitude. A current that flows in one direction but varies in intensity.

Pulse. Signal characterized by a steep rise from and decay toward an initial level. Pulse Shape definitions. A flow of electrical energy of short duration.

Pulse Amplitude. The magnitude of a pulse parameter, such as the field intensity, voltage level, current level, or power level.

Pulse-Amplitude Modulation. [PAM] Pulse modulation in which the amplitude of the pulses is varied by the modulating signal. Modulation in which the amplitude of individual, regularly spaced pulses in a pulse train is varied in accordance with some characteristic of the modulating signal.

Pulse-Code Modulation. [PCM] A modulation system in which the standard values of a quantized wave are indicated by a series of coded pulses. PCM Code Definitions. Modulation in which a signal is sampled, and the magnitude (with respect to a fixed reference) of each sample is quantized and digitized for transmission over a common transmission medium.

Pulsed Oscillator. A circuit that will only oscillate or sustain oscillation from external or internal pulses.

Pulse Droop. The slanting, or slow reduction in voltage of the top of a rectangular pulse, cause by loading, leakage or some form of distortion. Read more on Pulse Voltage Droop.

Pulse Duration. The time, during the first transition, that the pulse amplitude reaches a specified fraction of its final amplitude, and the time the pulse amplitude drops, on the last transition, to the same level. Read more on Pulse Shape definitions.

Pulse Duration Modulation. [PDM] Pulse modulation in which the time duration of the pulses is changed by the modulating signal. Refer to the Transistor Pulse Duration Modulator topic for a circuit example.

Pulse Duty Factor. The average of the pulse duration to the pulse separation.

Pulse Fall Time. [tf] The time it takes a voltage pulse to drop from 90 percent of its full value to 10 percent of its final value.

Pulse-Frequency Modulation. [PFM] Pulse modulation in which the modulating voltage varies the repetition rate of a pulse train. Modulation in which the pulse repetition rate is varied in accordance with some characteristic of the modulating signal.

Pulse Jitter. The variation in pulse to pulse spacing or arrival time. See Jitter.

Pulse Modulation. A form of modulation in which one of the characteristics of a pulse train is varied.

Pulse Oscillator. A sine-wave oscillator that is turned on and off at specific times. Also known as a ringing oscillator. Transistor Pulsed Oscillator Also refer to the Oscillator Manufacturers page.

Pulse-Position Modulation. [PPM] Pulse modulation in which the position of the pulses is varied by the modulating voltage.

Pulse-Repetition Frequency. [PRF] The rate, in pulses per second, at which the pulses occur. Same as Pulse Repetition Rate (PRR).

Pulse-Repetition Time. [PRT] Interval between the start of one pulse and the start of the next pulse; reciprocal of pulse-repetition frequency.

Pulse-Response. The resultant output from a circuit or system from receiving a pulsed waveform as an input. The circuit below shows a schematic of a test setup to measure the pulse response of a 2N718 transistor. The schematic provides the test points and input and output waveforms, and additional circuitry.

2N1613 Pulse Test Circuit
2N718 Pulse Response Test Circuit

Pulse Rise Time. [tr] The time for a pulse to rise from 10 to 90 percent of its peak value.

Pulse Stretcher. A circuit or IC that causes the duration of a pulse to increase or elongate. An IC that generates a long pulse after being generated by a short trigger pulse as in a 74121 Monostable IC, for example.

Pulse-Time Modulation. [PTM] Pulse modulation that varies one of the time characteristics of a pulse train (pwm, pdm, ppm, or pfm).

Pulse Transformer. A transformer that can handle higher than normal peak power outputs, compared to the average output power rating of other transformers.

Pulse Width. Duration of time between the leading and trailing edges of a pulse.

Pulse Width Modulation. [PWM] Pulse modulation in which the duration of the pulses is varied by the modulating voltage.

Purge. To remove unwanted data from a system or component. A Clear function on an IC chip.

Push Button Switch. A style of switch that is actuated by depressing a button. The graphic shows a Panel Mount [chassis mount] Push-Button Switch. Styles of Push-Button switches include Momentary and Latching switches. Also see Push-Button Switch Manufacturers.

Panel Mount Push-Button Switch

Push-Pull Amplifier. An amplifier that uses two transistors (or electron tubes) whose output signals are in phase opposition, with one amplifier working while the other does not. Read more about a Transistor Amplifier Push-Pull Circuit [on the companion site]. Also related; List of Transistor Manufacturers. Transistor Q1 operates while transistor Q2 is off in the circuit to the right.

Ruggedization. The process of taking a commercial product and adapting that product to accept a higher operating temperature and or a high shock environment and increased vibration. The term ruggedization is uncontrolled, so will mean different things to different companies. However; there are four common Semiconductor Temperature Ranges which could be used to differentiate increasing levels of ruggedization. The most common transition would be to take a commercial product and adapt that product to operate in a military environment.

PVC. Polyvinyl Chloride.

PC motherboard

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