Learning to read a light-emitting diode (LED) schematic is essentially the same as learning to read any electrical circuit, in that it is a process of learning to recognize different symbols and what they represent electronically. To read an LED schematic, you have to be able to identify wires, resistors, batteries, ground points and switches. After you have learned how to identify these signs, it is easy to read an LED schematic.
Electrical schematics are basically drawings that represent circuits and their components, which can then be read to either create a replica circuit or repair an existing circuit. The most basic sign used in electrical schematics is the sign for a conductor, or a wire. In an electrical or LED schematic, you will see straight, bold lines, which represent wires. When these wires intersect, a connection is shown by placing a dot at the intersection, and if they don’t connect, one wire is shown to arch over the other.
Batteries or other power sources are shown with a voltage rating, with plus and minus signs to show positive and negative outputs. Batteries are shown in LED schematics by a group of four long and short lines arranged alternatively. The shorter outer line represents the negative side of the battery. The power source is an integral part of an LED schematic.
A resistor in an LED schematic is shown by a jagged line. A resistor literally resists the flow of electrical charge, and the resistance is measured in units called ohms. If there is a “K” in the schematic beside the resistor, it simply refers to kilo-ohms. The jagged line is used in schematics because it conveys the fact that the current will not have as easy of a time passing through the resistor.
A switch is shown in an LED schematic by a broken section in the line, surrounded by two dots. The switch part of a circuit represents a point where the circuit can be switched on or off by the user. A light switch would be shown by the switch icon if you were to map out your room lighting as a schematic. The line breaks off at a 45-degree angle to show a switch in an LED schematic.
A ground point, although rarely necessary in LED schematics, is shown by a series of parallel lines gradually decreasing in size until they form a point. This gives the ground symbol the appearance of being triangular in shape. A ground point in a circuit is used to provide a way out for any excess current going around the circuit.
LED lights are shown in LED schematics by a black shaded triangle surrounded by a circle. There is a straight line at the tip of the triangle. These symbols are often labeled, and most circuit diagrams will include a key for uncommon signs.