# What are abbreviations used in electrical engineering?

This question is meant to be a glossary of abbreviations used in electrical engineering.

Some abbreviations are very common and universal, and are therefore acceptable to use on this site. Others are quite localized or pet abbreviations used by individuals without a wide following, so are not acceptable on this site. One purpose of this question is to list all abbreviations so that others have a chance to decode them if encountered, but thru voting also show which ones are acceptable to use in a wide international context or not.

So here are some rules to make this question work:

1. Each answer must only be for ONE abbreviation.

2. This will be community wiki, so only ONE answer for each abbreviation. If you want to expand on a description, edit the existing answer for that abbreviation.

3. This is going to get long, so consistant formatting will help. For each answer (abbreviation), start with just the abbreviation within HTML "h1" and "/h1" tags on a line by itself.

4. Upvote answers for abbreviations you think would be acceptable to use in a post on this site without any expansion or explanation.

5. Downvote abbreviations (answers) you think should not be used "bare" on this site. This will be community-wiki, so nobody will loose reputation as a result. In this special case, you are voting on the universality of the abbreviation, not on the quality of the writeup. If you don't like the write up, fix it instead.

# INDEX

A - A(2) AC(7) ADC(15) ALU(3) AM(7) ASCII(12) ASIC(6) ASK(1) AWG(7)

B - BCD(5) BJT(16) BLDC(4) BNC(6) BPF(1) BW(3)

C - CAD(5) CAN(7) CC(1) CC-II(-1) CCCS(1) CCD(6) CMOS(16) CMRR(1) COG(0) CPLD(4) CPM(-1) CPU(7) CRO(-1)

D - DAC(15) DC(7) DEMUX(2) DFT(2) DIP(5) DLL(2) DMA(7) DRC(3) DSO(3) DSP(13) DTFT(0) DVD(-10) DVM/DMM(4)

E - ECL(4) EDA(6) EE(7) EEPROM(13) EMC(3) EMS(-7) EOS(0) EPROM(3) ESD(9)

F - F(2) FDNR(-3) FET(17) FFC(2) FFT(6) FIFO/LIFO(7) FM(7) FPGA(9) FSK(1) FSM(4)

G - GBW(5) GIC(-1) GND(16) GPIO(9) GPS(4)

H - H(2) HDTV(-11) HF(4) hFE(2) HPF(2) HVSP(-1) Hz(3)

I - i(-1) I/P(-7) I2S(1) IC(11) IF(4) IFT(1) IGBT(9) IGFET(0) ISP(4) I²C(13)

J - j(-1) JFET(10) JTAG(7)

K - KCL(6) KVL(6)

L - LCD(17) LED(19) LF(3) LPF(4) LSB, MSB(2) LUT(5) LVD(-1) LVDS(5) LVDT(0) LVS(-2)

M - MCU(6) MEMS(6) MIDI(4) MOSFET(17) MPU(-1) ms(2) MUX(6)

N - NEXT(-6) NPN(12) NTSC(0) NVM(0)

O - O/P(-7) OCXO(2) OLED(4) OP-AMP(8) OTA(3)

P - P-P(0) PAL (logic)(2) PAL (television)(0) PC(-1) PCB(17) PCBA(-5) PCM(4) PFM(-2) PIC(0) PID(9) PLL(9) PM(0) , duplicate(0) PNP(14) POR(3) PPM(-1) PSK(5) PUT(-1) PWM(24)

Q - QM(-6) QVGA(0)

R - RADAR(0) RAM(12) RF(5) RFID(6) RGB(4) RJ45(6) ROM(3) RTL (discrete logic)(2) RTL (Verilog)(2)

S - SAW(3) SCR(9) SD,SDHC(0) SDCC(-3) SMA(4) SMPS(9) SMT(5) SNR(5) SOC/SoC(5) SPI(13) SPICE(8) SRAM(6) SRPP(-2) STA(0)

T - TBH(-8) TCXO(2) THD(6) TRF(-1) TTL(10) TVS(4)

U - UART(12) UHF(4) UJT(0) UL(3) USART(4) USB(4)

V - V(2) VCA(1) VCC / VEE / VDD / VSS(14) VCCS(1) VCO(5) VCXO(3) VFD(3) VGA(-2) VHDL(7) VHF(5) VLSI(2) VNL,VFL(-1) VSWR(4)

W - W(2)

X - XO(1) XOR(3) XTAL(5)

Ω - Ω(0)

186 answers - Sun May 11 09:17:28 2014 (CET)

# MIDI

Musical Instrument Digital Interface.

A standard for digital communication between electronic musical instruments, specifying both a protocol and hardware standards. MIDI data is usually transmitted over USB, or as a balanced serial data stream at 31.25kbps, using three conductors (+5V, signal, ground) and cables terminated in 5-pin 180° DIN plugs.

# UHF

Short for Ultra High Frequency (300 MHz ~ 3 GHz)

# HF

Short for "High Frequency".

# LPF

Short for "Low Pass Filter". Frequencies above the cut off frequency are attenuated.

• I have never heard this abbreviated like this, it would be nice to have someone weigh in as this is important in EE
– JFA
May 2 '14 at 0:25

# IF

Intermediate Frequency. Commonly used in Superheterodyne Receivers, where the tuned radio frequency is mixed down to a fixed intermediate frequency, where in turn the signal is demodulated to the audio band. Eg. for PAL TV 38.9MHz.

## VCXO

Voltage-Controlled Crystal Oscillator. A crystal oscillator that can be "pulled" away from its nominal frequency by means of an analog control voltage.

# VSWR

Voltage Standing Wave Ratio. In RF technology when a transmission line is not properly terminated, the voltage along the line will vary.

# ALU

Arithmetic and Logic Unit. The arithmetic and logic brain in a microprocessor.

# EPROM

Erasable Programmable Read-Only Memory. Non-volatile memory which preserves it contents even without a power supply. It may be erased by applying ultraviolet light onto the die. EPROM memories have been mostly replaced by EEPROM memories.

# ROM

Data persists after power is removed.

## EMC

ElectroMagnetic Compatibility. It's the discipline of electrical engineering concerned with controlling the electromagnetic radiation generated by electronic devices and the amount of such radiation that the devices can withstand/tolerate. Wiki

# VFD

Variable-frequency drive, a type of adjustable-speed AC motor drive

OR

Vacuum fluorescent display, a high-intensity segment display technology

# UL

Underwriters Laboratories, a company that certifies the safety of a wide variety of electrical products

# SAW

Surface Acoustic Wave filter

# LF

Short for Low Frequency, often audio spectrum (0 - 20kHz)

# HPF

Short for "High Pass Filter". A High Pass filter attenuates frequencies below the cut off frequency.

# hFE

The large-signal current gain of a BJT transistor. Defined as IC/IB in the forward-active mode.

• I rather think, this parameter hFE is defined as the SMALL-SIGNAL forward current gain in common emitter configuration.
– LvW
May 10 '14 at 9:11
• Can you provide a definition for Ic and Ib also in this summary? May 15 '14 at 6:20

Amplitude Shift Keying.

Simple modulation method used for digital communications in which digital data is represented as variations in amplitude of carrier wave.

# FSK

Frequency Shift Keying.

Simple modulation method used for digital communications in which digital data is represented as variations in frequency of carrier wave.

# DSO

Digital Storage Oscilloscope.

Electronic testing/measuring instrument which can store and analyze the signal digitally. DSO use LCD display to show the signals.

# VLSI

Very Large Scale Integration

# BW

"BW" is short for Bandwidth.

## ms

Millisecond - one thousandth (10-3) of a second

## µs

Microsecond - one millionth (10-6) of a second

## ns

Nanosecond - one billionth (10-9) of a second

## ps

Picosecond - one trillionth (10-12) of a second

# OTA

Operational transconductance amplifier Similar to an opamp, but an output current instead of an output voltage. Effectively a voltage controlled current source.

# OCXO

Oven Controlled Crystal Oscillator. Although a crystal oscillator is already pretty stable by itself, it does however vary its frequency with temperature. By keeping the crystal in a small oven and warming it to a given and stable temperature, the output frequency is no longer influenced by external temperature variations.

# TCXO

Temperature Compensated Crystal Oscillator. Although a crystal oscillator is already pretty stable by itself, it does however vary its frequency with temperature. By measuring the temperature and adjusting other parameter(s) of the oscillator circuit to compensate, the output frequency is less influenced by external temperature variations.

## H

SI symbol for henry (measure of inductance), abbreviated as:

## mH

Millihenry - one thousandth (10-3) of a henry

## µH

Microhenry - one millionth (10-6) of a henry

## nH

Nanohenry - 10-9 henry

## F

SI symbol for farad (measure of capacitance), abbreviated as:

## pF

• -1. I'm downvoting all the unit posts. Do we have a goal to go all the way to the First Principles? I think, it's safe to expect the posters to be familiar with the SI system. May 2 '14 at 5:52
• I agree that units probably shouldn't even be on this list, but at the same time, the down-votes make them look as though they are "unacceptable." I think they should at least have a positive score or be omitted from this list. May 2 '14 at 15:10
• @NickAlexeev The title of the original question is "What are abbreviations used in electrical engineering?". How do these not fit that criteria? A newbie, running across the term pF, probably doesn't know what that is. It's more likely they have only seen µF in schematics. May 2 '14 at 20:15

## W

Symbol for watt - measure of power (joules per second), abbreviated as:

## mW

Milliwatt - one thousandth (10-3) of a watt

## µW

Microwatt - one millionth (10-6) of a watt

## kW

Kilowatt - one thousand (103) watts

## MW

Megawatt - one million (106) watts

## GW

Gigawatt - 109 watt

• en.wikipedia.org/wiki/Long_and_short_scales May 1 '14 at 18:52
• @jippie -- I am using the short scales, each new term is 1000 times (or 1/1000 times) the previous. See en.wikipedia.org/wiki/Gigawatt#Multiples May 1 '14 at 22:04
• I'm not a native English speaker, but I thought 10^9 was commonly called billion. Whether it is the one or the other isn't really the point I wanted to make, my point is that it may be unclear for some. Other than that it is probably a detail we shouldn't worry too much about. May 2 '14 at 5:43
• @jippie Thx, that was a typo (cut and paste from another answer). May 2 '14 at 7:15

## A

SI symbol for ampere - measure of the amount of electric charge passing a point in an electric circuit per unit time, abbreviated as:

## mA

Milliampere - one thousandth (10-3) of an ampere

## µA

Microampere - one millionth (10-6) of an ampere

## nA

Nanoampere - 10-9 ampere

• I don't understand why such standard, common abbreviations as these would be down-voted. May 2 '14 at 15:09