April 25, 2011

Reference ID

Most schematic symbols are accompanied by labels. This “labels” maybe a combination of the following; reference ID, part number and value.
Reference ID is an identifier, such as “R1”, “C4” or “Q4”. The letter represents the type of component. The commonly used letters are R for resistor, C for capacitor, L for inductor, D for diode, Q for transistor and IC for integrated circuit. If there are several components of the same type in a circuit, the numeral suffix (as an example R2) is added to identify the particular component.
Part Number is used if the component is standard such as diodes, transistors and integrated circuits. For example 1N4001 is a commonly used diode or 555 is a commonly used integrated circuit which is used for timing purposes.
Value is used if the component does not have conventional part number. This is usually used for non-solid state components such as resistor, capacitor inductors.
Below are the most commonly used letters to designate a particular electronic component.
R – Resistor
C- Capacitor
L – Inductor
T – Transformer
D – Diode
LED – Light Emitting Diode
Q - Transistor
IC – Integrated circuit