L Coil; InductorLS Loud Speaker/Buzzer
M Measuring equipment, Meter
MH Mounting Hole
P Plug Type Connector (Most Moveable)
PS Power Supply
RResistor, or Potentiometer
RN Resistor Network
TB Terminal Block
TP Test Point
U Integrated Circuit or inseparable assembly
V Electron Tube, Photoelectric Cell
VR Voltage Regulator
W Cable Transmission or Wire Jumper or Busbar
Y Crystal, Oscillator
Resistance - That property of a material that impedes the flow of electrical current, reduces voltage and dissipates power in the form of heat in an electrical circuit. The unit of measurement for resistance is the OHM which is defined as the resistance required to maintain an electrical current of one AMP at One Volt.
1 OHM = 1AMP @ 1VOLT
The electrical symbol for resistance is the Ω or the Greek Letter 'Omega'.
Resistor- The Reference designator for the resistor per ANSI Y32.2 is R
One Thousand Ohms is abbreviated with K as in Kilo-Ohms (10K = 10,000 ohms)
One Million Ohms is abbreviated with M as in Meg-Ohms (100M = 100,000,000 ohms)
Resistors are available in Axial, Radial, Power D-PACK or TO-220, SIP arrays, SMT Chip packages and thick film embedded resistors that are screened or imaged into a printed circuit. Axial leaded carbon composition resistors come in 1/10W, 1/8W,1/4W, 1/2W, 1W, 2W 5W, 10W sizes... sized for the watts of power they can dissipate without being destroyed by the heat they generate.
Some sources for resistors would be Bourns, Dale, SRT, Rohm, Caddock... there are many.
Resistor Schematic Symbol
Resistor Color Code - A code for determining the value in Ohms of an axial leaded resistor.
See the Graphical Resistance Calculator - http://www.dannyg.com/examples/res2/resistor.htm
Black = 0
Brown = 1
Red = 2
Orange = 3
Yellow = 4
Green = 5
Blue = 6
Violet = 7
Gray = 8
White = 9
None = 20% Tolerance
Silver = 10% Tolerance
Gold = 5% Tolerance
RG cable - or coax as we know it, was developed by Bell Laboratories during WWII. Aircraft radio systems that required long-wire antennas, like for example long range bombers, needed a method to route the signal to either the belly or tail mounted long-wire reels without radiating within the fuselage. Bell Labs developed it and called this new cable Radio Guide or "RG".