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
R Resistance
r.f. Radio frequency
r.f.c. Radio frequency choke (coil)
r.m.s. Root mean square
R/A Right Angle ( 90 degree )
R/W Read/write
RAD Radians
RAM Random access memory
RCA The Radio Corporation of America
RCD Residual Current Device
RCF Recommended crossover frequency
RFI Radio Frequency Interference
RG Radio Grade (cable)
RIAA Recording Industries Association of America
RIDDOR Reporting of Injuries, Diseases & Dangerous Occurrences Regulation(s)
RJ Registered Jack
RMA Rosin, Mildly Activated
ROM Read only memory
rpm revolutions per minute
RSJ Rolled Steel Joist
RTC Resistive Temperature Compensation
RTC Real Time Clock
RTL Resistor transistor logic
RX Receiver