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Raspberry Pi
Raspberry Pi is a family of low-cost single-board computers and microcontrollers made by Raspberry Pi Ltd, whose profits fund a UK charity promoting computing education.
Raspberry Pi 3
Raspberry Pi 3 is a family of $35 single-board computers from Raspberry Pi, launched in 2016, introducing 64-bit processing and built-in Wi-Fi and Bluetooth to the line.
Raspberry Pi 4
The Raspberry Pi 4 is a single-board computer released in June 2019, the first Raspberry Pi with USB 3.0 ports, dual 4K micro-HDMI outputs, and USB-C power.
Raspberry Pi 5
Raspberry Pi 5 is the fifth-generation flagship single-board computer from Raspberry Pi, released in October 2023 and up to three times faster than its predecessor.
Raspberry Pi Holdings
Raspberry Pi Holdings, also known as Raspberry Pi Ltd, is a British company founded in 2012 that designs low-cost single-board computers; it listed on the London Stock Exchange in 2024.
Raspberry Pi OS
Raspberry Pi OS, formerly Raspbian, is the official Debian-based Linux operating system for Raspberry Pi single-board computers, begun by Mike Thompson and Peter Green in 2012 and renamed in 2020.
Raspberry Pi Pico
Raspberry Pi Pico is a $4 microcontroller development board launched by Raspberry Pi in January 2021, built around the RP2040, the company's first in-house microcontroller chip.
Raspberry Pi Zero
The Raspberry Pi Zero is a line of smaller, lower-cost single-board computers first launched in 2015 at $5, later including the wireless Zero W and Zero 2 W.
RASSOR
RASSOR (Regolith Advanced Surface Systems Operations Robot) is a teleoperated robotic excavator developed at NASA's Kennedy Space Center to dig, haul, and dump lunar regolith in very low gravity.
Rassvet (ISS module)
Rassvet is a Russian ISS module attached to Zarya, launched in 2010, used for cargo storage and as a docking port for Soyuz and Progress vehicles.
Raster graphics
Raster graphics, also called bitmap graphics, are digital images made of a rectangular grid of pixels, each storing a color; unlike vector graphics, enlarging a raster image can blur it.
Rat rod
A rat rod is a hot rod built in a deliberately rough, unfinished style with primer, bare metal, or surface rust, named by Hot Rod writer Gray Baskerville in the early 1990s.
Ratawi oil field
The Ratawi oil field is a major oil field in Basra Governorate, southern Iraq, and since 2023 the centerpiece of TotalEnergies' $27 billion Gas Growth Integrated Project.
RATCH Group
RATCH Group (บมจ. ราช กรุ๊ป) is a Thai power-industry holding company founded by EGAT in 2000, listed in Thailand as "RATCH", investing in electricity generation and energy businesses in Thailand, ASEAN, and Australia.
Ratchaburi Power power station
Ratchaburi Power power station is a 1,400 MW natural gas-fired combined cycle power plant in Ratchaburi province, Thailand, operated by Ratchaburi Power Company Limited, an affiliate of RATCH Group.
Ratchaburi power station
Ratchaburi Power Plant, also called RATCHGEN, is a natural-gas-fired power station in Ratchaburi province, Thailand, owned by RATCH Group. At 3,645 MW it is among Thailand's largest.
Ratchet (device)
A ratchet, also called a ratchet wheel or ratchet and pawl, is a mechanical device that allows motion in only one direction while blocking the reverse.
Ratcliffe-on-Soar Power Station
Ratcliffe-on-Soar Power Station was a 2,000 MW coal-fired power station in Nottinghamshire, England, and the last one operating in the UK when it closed in 2024.
Rate adaptation for 802.11
Rate adaptation for 802.11 is how a Wi-Fi transmitter adjusts its data rate to match channel conditions; the standard leaves the algorithm to vendors, with Minstrel the Linux default.
Rate gyro
A rate gyro is a gyroscope arranged to measure angular rate rather than attitude, using a spring-restrained gimbal; it serves in turn indicators, autopilots, spacecraft, and MEMS chips.
Rate limiting
Rate limiting is a traffic-control technique that restricts how many requests a client may make to a service in a time period, returning an error when exceeded.
Rate of change of frequency (RoCoF)
Rate of change of frequency (RoCoF) measures how quickly grid frequency changes, in Hz/s, after a generation-demand imbalance; it rises as inverter-based renewables displace synchronous generators.
Rate of convergence
Rate of convergence, also known as speed of convergence, is a numerical analysis characterization of how quickly a sequence of approximations approaches its limit, predicting iterations needed for a target accuracy.
Rate of fire
Rate of fire, also called firing rate, is the number of rounds fired per weapon per minute, the standard NATO measure, with cyclic, rapid, and sustained rates defined.
Rate transient analysis
Rate transient analysis (RTA) is a petroleum engineering method that uses production rates and flowing pressures to estimate permeability, fracture properties, and oil or gas in place without shutting in the well.
Rate-monotonic scheduling
Rate-monotonic scheduling is a fixed-priority, preemptive policy for periodic real-time tasks in which shorter periods get higher priority, proposed by Liu and Layland in 1973.
Rate–distortion optimization
Rate–distortion optimization (RDO) is an encoder-control technique in video and image coding that picks coding modes by minimizing reconstruction distortion subject to a bit-rate constraint, using the Lagrangian cost J = D + λ·R.
Ratel IFV
The Ratel, or Ratel20 in its standard variant, is a South African 6x6 wheeled infantry fighting vehicle carrying a 20-mm cannon, in service since 1976 and the first wheeled IFV.
Rateless coding
Rateless coding, also called fountain coding, is a forward error correction technique generating as many encoding symbols as needed, so any slightly larger set of received symbols recovers the data.
Rating system of the Royal Navy
The rating system of the Royal Navy categorized British sailing warships into six rates by crew size and later by guns, from the early 17th century to the mid 19th.