Glossary of Terms

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Displaying all terms.

2-wire Resistance:
A standard method for measuring resistance by connecting two test leads across a resistance.
4-wire Resistance:
A method for measuring resistance that provides better accuracy by eliminating the resistances of the test leads into the calculation. Usually, it consists of using four independent test leads to measure across a resistance, with one pair connected to a voltmeter and another to an ammeter. Special tools called Kelvin clips or probes are commonly used for this measurement to avoid contacts between the wires that may introduce stray resistance to the measuring circuit.


Absolute Humidity:
Refers to the mass of water in a particular volume of air. Absolute humidity is expressed as the number of kilograms of water vapor per cubic meter of air.
Accelerating voltage:
The internal voltage that accelerates the electron beam and causes trace illumination on the oscilloscope display.
States how closely an instrument indicates the actual value of a measured unit. Accuracy is usually indicated as an error percentage. Zero percent would indicate a perfect meter. Unless indicated, the accuracy percentage will be of full scale.
The ratio of power in the range specified by offset frequency and bandwidth to carrier power.
Amp x h, a standard unit to measure a battery's total capacity. It represents how much constant current (A) can be provided in an hour before the battery becomes insufficient in providing power. For example, 10Ah capacity means the battery can provide a 10A current continuously for an hour.
Amplitude Modulation, often used to broadcast audio signals to consumer radios.
Generally defined as a measurement unit for the vertical length of a wave or signal.
A device for measuring airflow or the pressure of moving air. The term is derived from the Greek word "anemos" meaning wind.
Abbreviation for Arbitrary Waveform Generator
Arbitrary Waveform Generator:
A signal generator that can generate waveforms with an arbitrarily defined shape other than the standard Sine, Square or Ramp waveforms found on function generators.
A measured ratio between the width and the height of a video display signal. The standard NTSC signal has an aspect ratio of 4:3. Other common aspect ratio such as 16:9 applies to HDTV and some DVD video.
A decrease in signal amplitude, generally measured in the unit of decibels (dB).
A feature which automatically selects the capacitance range that will provide highest resolution.
Averaging RMS:
The average value of a sine wave is 0.637 times the peak value, while the rms value of a sine wave is 0.707 times the peak value. This value varies depending on the type of wave being measured. For example, a triangle wave will have an rms value of 0.577 times the peak value.
Initialism for Arbitrary Waveform Generator


The bandwidth is one of the most important specification when defining an oscilloscope as it represents the range in which an oscilloscope can display frequency accurately. The bandwidth is defined by the frequency response curve when the attenuation is at the -3dB mark. As a general rule of thumb, the oscilloscope's bandwidth should be at least five times the highest frequency of the signal under test.
Battery Internal Resistance:
Internal resistance represents the internal chemical behaviors of a battery in the form of electrical circuitry. It is often measured to determine the life of a battery, indicating whether a battery can recharge further for use or not.
A parameter variable defined by a user, it is used to set the speed of data transition when interfacing via RS232 serial port to a PC. It is measured in bits per second (bps). Typical baudrates are usually: 2400bps, 4800bps, 9600bps, 19200bps, 38400bps, 57600bps, 115200bps.
Bipolar Transistor:
Commonly abbreviated as BJT, it is one of the major types of three-terminal semiconductor devices. It consists of two pn junctions that are connected in series, therefore having current be conducted by both electrons and holes.
A wireless technology often used for close range wireless communication. They are widely used in wireless devices such as cellular phones, computer peripherals, and electronic music players.
Bayonet Neill Concelman connector is a standard for transmitting video signals via coaxial cable. It is also often found in measurement devices as a connector interface for sending waveform signals.
Band pass filter.


The luminous intensity, in a given direction, of a source that emits monochromatic radiation with wavelengths weighted to the standardized model of sensitivity of the human eye.
A measurement that often characterizes the amount of charge stored in capacitors. The standard equation for capacitance is C = Q/V, where C stands for capacitance, Q is the charge on the parallel plates, and V is the voltage across those plates. It's generally measured in the unit, Farad (F).
Capacitance Meter:
A test instrument used to measure capacitance of electronic components.
A physical electronic component that consists of a pair of parallel plates used for storing energy inside an electric field that exists in between them.
Carbon Dioxide:
A chemical compound composed of one carbon and two oxygen atoms. It is often referred to by its chemical formula CO2 (the "2" is subscript).
Carbon Monoxide:
A toxic, colorless, odorless, and tasteless gas. It consists of one carbon atom covalently bonded to one oxygen atom and has the chemical formula CO.
CAT Rating:
The International Electrotechnical Commission (IEC) has defined voltage category ratings (CAT ratings) that indicate an instrument's ability to withstand voltage spikes. The usage for each CAT level is defined as: - CAT I Signal level, telecomm electronics, special equipment - CAT II Appliances, portable electronics - CAT III Fixed installs, distribution level mains - CAT IV Service drop to outside building
Abbreviation for constant current, which is the most common mode of operation in any type of DC electronic loads. When a DC electronic load is setup in this mode, it sinks a current value, usually defined by user, constantly. This mode is often used in battery testing and analysis.
Code Division Multiple Access, a wireless communication transmission system often implemented in cellular phones.
Formerly Centigrade - A thermometric scale in which the freezing point of water is 0°C and its boiling point 100°C at normal sea level atmospheric pressure (14.7 psi). °C = (°F-32)/1.8.
The sum of power in the band specified by bandwidth and band center.
Charge Capacity:
Indicates the capacity of charge in a battery, which determines the amount of power a battery can provide before it is used up.
Carbon Monoxide
Carbon Dioxide
One of the most typical pattern for testing television, color bars follow certain standards specified by the television system such as NTSC where they are a display of bar pattern with a prescribed luminance and chrominance levels and phase.
Common Mode Rejection Ratio:
A ratio of common mode voltage to input voltage, indicated as an error by the instrument.
Common Mode Voltage:
A voltage common to both input terminals of a meter such as power line common, earth ground, or external power supply common. Common Mode Voltage can cause error in measurement.
Component is a video output that splits the video signals into three different channels. They are often seen as input video connectors in televisions and are often labeled Y, Pb, and Pr.
Often refer to as a video output with a preset of 1 volt peak-to-peak amplitude or variable 0 to 1.5 volt peak-to-peak amplitude into standard 75 ohm impedance.
Constant Current:
A regulated power supply that delivers a constant current to a load, even when the load resistance changes. Note that the power supply must follow Ohm's Law.
Constant Voltage:
A regulated power supply that delivers a constant voltage to a load even when the load resistance changes to a value that will not exceed the power supplies current limit.
Continuity Test:
A test usually accompanied by a buzzer sound to determine if the circuit under test has continuity, meaning its resistance is relatively low.
A unit of measurement that defines the resolution a multimeter is capable of reading. The count value determines the limit point at which a multimeter will read before it loses resolution by one decimal point. For example, a 50,000 count multimeter will be able to read 49.999 volts, but at 50V, the multimeter may read 050.00 volts, losing one decimal place of resolution.
Abbreviation for constant power, it is a mode of operation found in DC electronic loads. When set to it, the load will draw a constant amount of power based on the user's selection, from any power source connected to the load.
Commonly known as constant resistance, is a common mode of operation in a DC electronic load. Under this mode, a DC load acts like a resistor set at a fixed value.
Crest Factor:
A ratio of signal peak to rms value. Defines the limits within which a true rms meter will accurately measure.
A 19 x 15 pattern of two or more intersecting parallel lines.
Also known as channel isolation, is the undesired effect that a signal on a channel has on another separate channel.
Cathode Ray tube
Stands for constant voltage. It is a frequently used mode of operation in a DC electronic load when testing power supplies. When set, it will draw a set voltage to its terminals.
See CP.


Data Hold:
A feature which, upon pressing a button holds (or freezes) the instantaneous reading on the display at the time the button is pressed.
Data Logger:
An electronic instrument that records data over time.
A mathematical unit of measure, generally included as a feature in a multimeter for expressing DC and AC voltage, that minimizes the scope for a large range of measurements. It is often used to define the gain or signal-to-noise ratio. The formula to convert voltage to dB is: dB = 20 log (Vin / Vref) where Vin is the DC or AC voltage input and Vref is a reference voltage level.
A unit of measure that indicates the power ratio of a signal to the carrier signal. It is often used to indicate phase noise, along with a frequency offset from the carrier frequency.
A mathematical unit of measure, often provided in a multimeter as a measurement tool to define a value in decibels above or below a 1mW reference. In general, 0dBm means the amount of voltage required to dissipate 1mW through a reference impedance is applied. The formula to calculate dBm is: dBm = 10 log (((Vin)^2 / Zref) / 1mW ) where Vin is the DC or AC voltage input and Zref is the reference impedance defined by user.
DC Bias:
A DC current required to achieve an intended amount of inductance.
DC Offset:
Settable DC voltage superimposed on the output signal. Used to match the DC voltage at the point of signal injection or for other special applications..
Stands for Direct Digital Synthesis, an implementation technique in newer arbitrary function generators that produces stable and more accurate output, displaying clean sine waves with minimal distortion. Additionally, this technology can minimize the rise and fall times when generating square waves.
A measure of the ratio between two quantities, and is used in a wide variety of measurements in acoustics, physics and electronics. The decibel is widely used in measurements of the loudness of sound.
Delayed Time Base:
A feature in some oscilloscopes that allows a single signal to be viewed at two different time bases with the second time base expanding a portion of the waveform and starting at some point after the main time base begins. This is often useful for magnifying display.
Used for measuring the difference of frequency and level between two marker points on a frequency spectrum.
Dew Point:
The temperature at which a given parcel of air must be cooled at a constant barometric pressure for water vapor to condense into water.
Digital Multimeter:
A Digital Multimeter , also known as a DMM, Volt/Ohm Meter or VOM, is a piece of electronic test equipment that incorporates multiple features and functions for testing parameters other than voltage, current and resistance.
Digital Storage Oscilloscope:
An oscilloscope the digitizes the input signal before displaying it.
This is a common way that defines the resolution range, similar in respect to Counts. The values have specific meanings. For example, a 4 1/2 digits multimeter means it can read up to 4 digits from 0-9, while the 1/2 means it can read one digit from 0-1. Meaning, it can read 20,000 counts. This translates to reading within the range from 00000 to 19999. So the meter can read 19.999 volts, but at 20V or higher, it will lose a decimal point in resolution and read as 020.00 volts.
Dual inline memory module, a type of memory often found in first generation DDR main memory for computers.
A common electronic component that has one direction of current flow. They are often used in power supplies and rectifiers for AC to DC voltage conversion.
Dual inline package, a chip packaging generally designed for ICs and microprocessors.
Dissipation Factor:
The Dissipation Factor (or D) is considered equal to the power factor of a dielectric, which is the cosine of the phase angle by which the current leads the voltage. The Dissipation Factor is usually measured during the measuring of capacitors. It is also the reciprocal of Q.
Digital light processing, a technology used for projection of video images.
Is the abbreviated name for Digital Multimeter
Stands for dynamic random access memory, it is a volatile memory that loses data once power is not connected to it.
Distance to spot
Digital Storage Oscilloscope (also known as a Digital Scope or Digital OScope)
Dual tone multi-frequency, a term used to refer to a waveform having a signal with two different frequencies combined. This is implemented especially in telephone system, where the number keypads each generate a DTMF signal that sends to an operator.
Dual Trace:
A feature in most oscilloscopes that allow the display of two different traces, usually for comparing and analyzing more than one signal at a time.
Duty Cycle:
Duty cycle is a unit of measure that takes into account the ratio between the width of a pulse signal before a transition and the total time period of one pulse cycle. Pulse width period divided by pulse repetition period.


Electric field
Edge Trigger:
A common feature found in oscilloscopes in which triggers an input signal when it detects an edge in the signal. An edge is usually the part of a waveform where there is either an increase or decrease in voltage or current level.
Electrically erasable programmable read only memory, often found in electronic devices for storing data or information of small size. This is most often used in test instruments for storing settings or configurations for recall at a later time.
Electromagnetic Interference
Usually written e, is the ratio of energy radiated to energy absorbed by a black body at the same temperature. It is a measure of a material's ability to absorb and radiate energy. A true black body would have an e = 1 while any real object would have e < 1. This emissivity depends on factors such as temperature, emission angle, and wavelength. However, a typical engineering assumption is to assume that a surface's spectral emissivity does not depend on wavelength, so that the emissivity is a constant. This is known as the grey body assumption. When dealing with non-black surfaces, the deviations from ideal black body behavior are determined by both the geometrical structure and the chemical composition.
Stands for equivalent series resistance, which is a measurement primarily used to define the performance of an electrolytic capacitor. They are measured to be internal resistances that are in series with a desired capacitance at certain frequencies.
ESR Meter:
A test equipment tool to measure the equivalent series resistance.
This term refers to a standard type of technology often associated with computer networking. Ethernet adapters have RJ45 adapters for connecting a cable from PC to network.


A thermometric scale in which 32°F denotes freezing and 212°F the boiling point of water under normal sea level atmospheric pressure of 14.7 psi. °F = (1.8°xC) + 32.
Fall Time:
The time it takes for a signal to fall from a higher level to a lower level in value. The level is often either for voltage or current.
Field Effect Transistor, consisting of three terminals: gate, drain, source.
A type of non-volatile memory commonly used for storing data from a computer. They are used in many electronic devices such as cellular phones, digital cameras, and even solid state hard drives.
Frequency Modulation, often used for broadcasting audio signals to consumer radios.
Can also be called as luminance per square foot is a standard unit of luminance. It is "the illuminance cast on a surface by a one-candela source one foot away". 1fc is approximately equal to 10.764lux
Field Programmable Gate Array is a device that allows logic programming with hardware description languages such as VHDL or Verilog.
The rate at which a complete television picture is displayed, which includes all the vertical and horizontal lines. It is often measured in frames per second (fps).
A measurement that often defines the length of a wave and is inversely related to the period of a wave.
Frequency Response:
A band of frequencies over which the instrument will measure without exceeding a specified percentage of error. Usually but not always limited to a reference of 50/60Hz measurements.
Also known as frequency shift keying, is a type of frequency modulation scheme, primarily used for transmitting information by converting signals into specific frequency and transmitting them over wires.
Function Generator:
A signal generator capable of generating sine, square, and trianlge outputs.


Gate Time:
In a frequency counter, the gate time is the amount of time to wait before the next frequency measurement is made.
Gated Tone Burst:
Function generator provides output only for the duration of an external pulse.
General Purpose Interface Bus also known by its Institute of Electrical and Electronics Engineers standard IEE-488.
Global System for Mobile communications


Magnetic field
Half sine wave.
High definition television, which differs from traditional television that mostly uses analog TV signals for picture display. HDTV uses digital TV signals that can provide content with a much higher resolution. This is often measured as 720p or 1080p, which translates to the vertical resolution of the picture based on the number of pixels. The "p" here presents the scanning system, which in this case means progressive scan.
The energy that an object has because of its temperature. Heat is different from temperature (q.v.) because an object with twice as much mass requires twice as much heat to increase its temperature by the same amount.
Heating, Ventilation & Air Conditioning


The quality or composition of interior air that could affect health and/or comfort of a building's contents or occupants.
Integrated circuit.
A measurement that is defined in terms of emf, electromotive force, that is generated to oppose any change in current. The unit for measurement is in Henry (H).
A circuit element, usually made of a coil of wires, that stores energy in a magnetic field when electric current passes through it. It is often used as a component in power supplies or as a pair to create a transformer.
Infrared Radiation:
Form of electromagnetic radiation with a wavelength between 0.7 and 100 micrometers (um).
Often defined for spectrum analyzers, it defines the limit of the level (usually measured in dBm) of a signal that can input into the instrument.
Input Impedance:
The combined AC and DC resistance at the input of a Multimeter. In most cases you will see input impedances of 10 Mohms or greater for low DC voltage measurements. This virtually assures freedom from loading in most types of circuits.
The opposite of progressive scanning, this scanning system scans every other horizontal lines of a signal at each frame and alternates after each frame. Meaning, it wills can all odd lines first, then scan all even lines.
Internal Resistance:
This term is used often to model the reactions of a battery in electric circuitry. The inside of a battery is considered an internal resistance, in which increases overtime as the battery discharges.
Infrared radiation
Floating output, no reference to any voltage.
In-circuit programming or in-system programming is a type of serial programming that allows you to program a chip while it is already connected in a complete system, as opposed to programming before putting into a system.


Is the abbreviation for Liquid Crystal Display.
An abbreviation signifying inductance (L), capacitance (C), and resistance (R).
LCR Meter:
A multifunction instrument which measures inductance (L) of coils or inductors (and other inductive devices); capacitance (C) of capacitors or components and resistance (R) of carbon resistors or any non-inductive component.
Lead Acid:
Refers to the chemicals used for making a battery. Ideally, these are used for the type of batteries used in automobile.
Is the abbreviation for Light Emitting Diode. It is an electronic component that produces a bright light and has a long lifetime.
Abbreviation for lithium ion, is one of the most popular type of rechargeable batteries used today to provide longer lasting power than Ni-MH batteries for portable electronics such as cellular phones and laptop computers.
Line Regulation:
How much the load voltage or current changes when the power supply is operated at varying line voltages throughout a given range. Typically stated as a percentage of the total voltage or current available from the supply. A rating of "0%" would mean perfect regulation.
Linear Power Supply:
Uses a transformer to convert the voltage from the mains to a different voltage.
A perfectly linear sweep would be produced by a perfectly linear sweep ramp, meaning that any variance in the sweep ramp would cause the time represented by one horizontal division on the display to be unequal to the time.
Load Regulation:
How much the load voltage or current changes between operating the power supply at no-load and full-load conditions. Typically stated as a percentage of the total voltage or current available from the supply. A rating of "0%" would mean perfect regulation.
Low Voltage Characteristics:
Often indicated as part of the specification or as a graph, it illustrates a DC electronic load's ability to produce maximum current at minimum voltage. It is used as a performance measure of a DC load for low voltage, high current applications.
The lux symbol is lx and is a standard unit of luminance. It is used in photometry as a measure of the perceived intensity of light. 1lx is approximately equal to 0.0929fc.


Milli-amp x h, a common unit of measure to indicate a battery's total capacity. This is often used to indicate capacity of consumer type batteries of type Ni-MH or Li-Ion.
Measurement Rate:
The number of times per second that the test or measurement is updated.
A pattern generated by NTSC generators for checking horizontal resolution and bandwidth. Often, the pattern includes bursts of sine wave video at various frequencies of dc. This wave radio produces alternative black and white lines. As frequency increases, lines in the pattern becomes closer together.


A logic gate that performs in a way where when two logic signals are 0's, output will be1. If both are 1's, output will be 0. If only one of either is a 1 and other is 0, it will be 1.
Abbreviation for nickel metal hydride, is a popular type of rechargeable batteries often used for powering portable electronic devices.
The portion of unfiltered and unshielded EMI noise present at the output of a filtered power supply, operated at full load. Typically stated in peak-to-peak AC voltages (with zero volts peak-to-peak representing a perfectly filtered & shielded power supply).
A logic gate where it performs opposite of NAND in a sense that when two logic signals are 1's, output is 0. If they are opposite of each other, output would be 0. If they are both 0's, output is 1.
Normal Mode rejection Ratio:
A ratio of peak normal mode voltage to the equivalent pass band voltage, indicated as an error by the instrument.
NPN refers to a type of bi-polar junction transistors (BJT), which consists of three regions: n-type emitter, p-type base, n-type collector. The normal current flow of the emitter in a NPN transistor has a forward direction from base to emitter.
Stands for National Television System Committee, often referred to as the television system used primarily in countries such as United States and Canada. Under this standard, 525 horizontal lines of interlaced scan is performed in the transmission process.


Defined by the width of points that have a certain dB level, defined by user, lower than the peak level of a frequency spectrum.
Abbreviation for Over Current Protection. It is the maximum current limit allowed before going in to OCP mode to protect both the instrument and the device under test.
Organic LED
Occupational Safety and Health Administration is an agency of the United States Department of Labor. Its mission is to prevent work-related injuries, illnesses, and deaths by issuing and enforcing rules (called standards) for workplace safety and health.
Overload Protection:
The means by which a power supply is protected from permanent damage due to short circuits, excessive loads, or reverse polarities connected across the load terminals. Protection may be as simple as a fuse (which can be economically replaced), or may be electronic protection conditions as well as power supply component temperatures.
Abbreviation for Over Voltage Protection. It is the maximum voltage limit allowed before going in to OVP mode to protect both the instrument and the device under test.


Phase alternating line, a type of color encoding system for television in some countries. This is widely used in Europe. Under this standard, 625 lines of of horizontal resolution at 50Hz is used.
Parallel Measurement Mode:
Usually for Resistance and Capacitance measurements of Resistors and Capacitors
Peak Hold:
A feature which holds the highest value attained during a measurement of changing levels of voltage or current.
A measurement that often defines a full cycle of a wave before it repeats again. It is inversely related to frequency and it is measured in time.
A measure of the acidity or basicity of a measurable substance. Substances with a pH less than seven are considered acidic, while those with a pH greater than seven are considered basic (or alkaline). pH 7 is defined as neutral, because it is the pH level of pure water at 25 °C.
Stands for plastic leaded chip carrier, it is a programming socket type with four sides that has leads ranging from 20 to 84.
Programmable logic device.
Phase lock loop
Also known as phase modulation, is a type of modulation in which the instantaneous phase changes are proportional to the signal to be transmitted.
In a way, PNP is another type of BJT and is opposite of NPN transistors. The emitter region is p-type, base region is n-type, and collector region is p-type. The normal current flow of the emitter in a PNP transistor has a forward direction from emitter to base, which is opposite of NPN transistors.
Power Consumption:
The input power that is required by the power supply at a full load output condition.
Abbreviated for Parts Per Million, literally meaning 1 PPM = 1/1,000,000. It is an alternate unit of measurement, often used in place of percentage unit for indicating resolution and accuracy. The following is a conversion list between PPM and Percent: 1 PPM = 0.0001%, 10 PPM = 0.001%, 100 PPM = 0.01%, 10000 PPM = 1%.
Able to be programmed either by the front panel or by a connected PC.
The counter part of interlace scanning, this scanning system scans all horizontal lines of a signal at every frame, providing a smooth transition from frame to frame in video imaging.
Pulse Trigger:
Defined as a triggering method that uses a pulse waveform, generally with a TTL voltage level, to signal when to trigger off a device. This is often used with an oscilloscope to trigger a waveform capture at a particular instance.
Pulse Width:
Period of time (usually in micro seconds) that the pulse is high.
Pulse width modulation, a type of modulation that takes into account the duty cycle of a signal and modulating it to transmit information. They are often used for controlling analog circuits based on information in digital form. One of the most popular application is a CPU fan inside a computer that changes in speed based on temperature conditions.


Quad flat package, often used in chips for NOR flash memory and similar to PLCC packaging.
Quality Factor:
The Quality Factor (or Q). The Quality Factor is usually measured during the measuring of inductors. It is also the reciprocal of D.


Raster is a type of pattern that is generally used for scanning from side to side with lines that are vertical.
This is a measurement function found in some frequency counters to calculate the ratio of frequency between two different signals.
Resolution Bandwidth
Recovery Time:
The time that it takes a power supply to regulate its output after an abrupt change, such as from full load to no load.
The ability to maintain a constant voltage or current at the load despite changes in line voltage or load resistance.
Relative Humidity:
The ratio of the current vapor pressure of water in any gas (especially air), known as the absolute vapor pressure, to the equilibrium vapor pressure or saturation vapor pressure, at which the gas is called saturated at the current temperature, expressed as a percentage.
Relative Mode:
A common measurement function in a component tester that allows you to make relative measurements in a specified range.
Remote Sense:
Ensures that the voltage at the load is the same as the power sources set voltage. The remote sense feature compensates for any voltage drop between the source and the DC electronic load.
Repetition Rate:
Number of times that a pulse recurs in one second.
A measurement that indicates the amount of current given a potential difference. The standard formula to compute this measurement in electronic circuits is R = V/I, and the unit is ohm, often indicated by the Greek symbol omega.
Generally made of resistive wires, it is a circuit element that produces a voltage drop across its two terminals.
The smallest increment of change that can be indicated on a display.
Radio frequency, which is also generally used to specify high frequency electronics and applications such as wireless devices and radio communications.
A color model that uses a mix of red, green, and blue colors to represent a wide range of colors. This is often used in CRTs, TVs, and LCDs.
Relative humidity
Ripple Current:
The portion of unfiltered AC current at the output of a filtered power supply.
Ripple Voltage:
The portion of unfiltered AC voltage and noise present at the output of a filtered power supply, operated at full load. Typically stated in rms AC voltages (with zero ripple voltage representing a perfectly filtered power supply).
Rise Time:
The time it takes for a signal to rise from one level to another level of higher value. The level is often either for voltage or current.
Standard telephone jack adapter.
Standard Ethernet jack adapter.
Is the abbreviation for Root Mean Square. It is the peak voltage of a sinusoidal waveform, times the square root of one half.
Revolution per minute. This is a feature in some frequency counters that converts the frequency counters into revolutions per minute.
Recommended Standard 232 serial interface.


Sampling Rate:
Specifies the rate of which a waveform or signal is sampled. It is one of the main specifications typically defined for oscilloscopes to demonstrate the number of data samples they can display, often measured in the units of samples per second.
Abbreviation for Standard Commands for Programmable Instruments.
An abbreviation for silicon-controller rectifier, is a rectifier that consists of four layers. It can be simplified as two BJT transistors, one PNP and one NPN, connected between the base and collector regions of the PNP to the emitter and base junction of the NPN transistor respectively. A SCR often has a very high voltage rating.
Synchronous dynamic random access memory, meaning that it responds with a clock signal, as opposed to asynchronous in which it responds to changes as fast as possible.
Series Measurement Mode:
Usually for Inductance measurements of Inductors or any component that has inductive properties.
Signal Generator:
Any device that generators repeating or non-repeating electronically produced signals. Encompasses function generators, sine wave generators, audio generators, pattern generators, arbitrary waveform generators, arbitrary function generators, rf generators, and DDS generators.
Sine Wave:
Sinusoid wave that is a function with its most basic form is: y = A x sin(wt + p) where A = amplitude, w = radians per second, t = time, p = phase or phase shift.
Sealed lead acid
Slew Rate:
Defined as the rate that corresponds to the speed of a DC electronic load's response to changing current. Generally, it is measured by allowing the DC electronic load to draw current from 0 to its rated current and measuring the steepness of the slope between 10% and 90% of this change on a current graph over time.
A Connection type generally used for RF or high frequency transmission.
Small outline dual inline memory module, a common type of memory often found in older laptops with 200-pin connections. They are similar to DIMM, but comes in a smaller size.
This packaging, called surface-mounted IC, is a small outline IC that is much smaller than a DIP packaged chip.
Usually represented as a graph displaying information on the voltage levels of a range of frequencies. This is also called frequency spectrum.
Square Wave Symmetry:
A measurement of the equity of both halves of a square wave cycle.
Single side band
Amount of amplitude change (Amplitude Stability) or frequency change (Frequency Stability) over a specified period of time after the unit is thoroughly warmed up.
Generated NTSC prescribed staircase pattern of 5 equal steps of increasing luminance of gray-scale. Often this pattern is used for checking linearity of luminance and chroma gain, differential gain, and differential phase.
The motion from left to right that causes a trace to appear. For example, a sweep time of 0.1mS/div means that the trace moves from left to right across one division in 0.1mS.
Sweep Generator:
The signal generator output repeatedly sweeps through a band of frequencies usually selectable between linear or logarithmic rate of frequency change.
Sweep Rate:
Rate at which a sweep generator repeats a sweep cycle.
Sweep Width:
The frequency band that the sweep generator covers. Some sweep generators have settable start and stop frequencies.
Switching Power Supply:
Uses transistors instead of a large transformer to convert the voltage from the mains to a different voltage.


Time division multiple access, a system widely implemented in cellular phones for wireless communication to a network.
What a thermometer measures. Temperature is the average kinetic energy per molecule.
Temperature Coefficient:
The change in power supply output voltage that is caused by temperature change. It is usually expressed in millivolts per degree (mv/degrees C).
Thin film transistor, often used for LCD displays.
Abbreviated as total harmonic distortion, is a measurement of a signal in which indicates the ratio of the total sum of the powers of all harmonic frequencies above its fundamental frequency over the power of the fundamental frequency of the signal.
In electronics, thermocouples are a widely used type of temperature sensor and can also be used as a means to convert thermal potential difference into electric potential difference. They are cheap, interchangeable, have standard connectors, and can measure a wide range of temperatures. The main limitation is accuracy; system errors of less than 1 �C can be difficult to achieve.
Time Base Accuracy:
Defines the accuracy of the time base, which represents the time per division on an oscilloscope display.
Thin quad flat pack, a package type in chips with leads ranging from 32 to 176.
Two power supplies (within on case) that are electrically coupled so that both can be varied by using only one knob.
A signal source that generates sine waves that are synchronized with the sweep of a spectrum analyzer.
Transient Response Time:
The time it takes for the output voltage to recover to within a certain voltage (usually 15mV) following a change in output from full load to half load (or vice versa)..
A common circuit element used for switching electric signals both in digital and analog circuits. Two of the most popular types of transistors are the bipolar junction transistors (BJT) and metal-oxide semiconductor field-effect transistor (MOSFET).
A three-terminal device similar in construction and operation to an SCR. A TRIAC controls and conducts the current flow of both alternations of an AC cycle.
Triangle Wave Linearity:
A measurement of the slope "straightness" of the triangle waveform generated by a generator. Measured as a percentage where 100% is perfect.
Signal that causes an oscilloscope to begin sweeping across the display for a trace. This can also be considered a event in which storage process is referenced in a digital storage oscilloscope.
Trigger Level:
Usually set as the vertical level, in which is set to be the trigger when a trace has an amplitude that equals to or greater than it. Trigger is set off immediately when this even occurs.
Triggered Mode:
When a signal generator or function generator provides one cycle of the output each time it is externally triggered. It is often used to synchronize the output to an external source.
True RMS:
The true and accurate RMS measurement of a non-sinusoidal waveform.
Thin small-outline package, usually come in two different types. These types of packaging of chips are most often utilized in flash memory ICs.
In some instruments, TTL logic is used for the serial port to transmit signals between instruments to PC interface. TTL logic levels are typically based upon a certain voltage level of a power supply. In most cases, this voltage is 5 volts. Depending on the voltage, different signals are transmitted via serial port.


Universal Serial Bus.


DC output voltage proportional to frequency.
Abbreviation for Volt-Ampere. Unit of input power delivered to a load. For electronic equipment, the "V/A" load imposed on the isolation transformer or AC power supply is simply the load voltage multiplied by the load current, or the wattage rating of the load.
Video Bandwidth
Voltage Controlled Generator is a generator that changes the output frequency by varying an external DC control voltage.
Video Sync:
Sometimes referred to as TV sync, video sync allows vertical or horizontal video sync pulses to be selected for triggering. Vertical sync pulses are selected to view vertical fields or frames of video and horizontal sync pulses are selected for viewing horizontal lines of video.
VM Comp:
Often an option in a multimeter, it stands for voltmeter complete. It is generally a BNC terminal that provides a low-true pulse after each measurement has completed. In short, it is a complement with external trigger that is used as part of a handshake sequence between switching devices and measurement.
The device most often used to measure return loss when using tracking generator to observe amplitude frequency characteristics.


Zero insertion force socket.