If a power source has an alternating current (AC), you’ll see a squiggly line drawn in the middle of the circle. If the power source has a direct current (DC), you’ll see a plus and minus sign on the top and bottom of the circle, respectively. Constant power sources are indicated with a downward facing arrow in the middle of the circle. The power source sends different types of electrical currents throughout the circuit.
Conductors aren’t represented by any type of fancy symbol.
Electrical loads might be difficult to identify in complex schematics. Try looking up pictures of simple electrical loads to get the basic idea.
Variable resistors look like a zig zag line with a diagonal line going through the center. [5] X Research source
You might see a plus sign in the top left corner of the capacitor symbol. This indicates that the capacitor is polarized. Some capacitors are made with curved horizontal lines.
Physically, inductors are coiled pieces of wire, which explains their shape in the schematic.
The switch opens and closes the flow of an electric current. Some switches might not have open circles at all. The lines represent “poles,” while the circles represent “throws. ” The most simple switch is known as a “single-pole/single-throw. ” The open circles represent the terminals in the switch.
Transistors will have 2 angled lines entering and exiting the long vertical line. One of these lines will be an arrow.
More complex symbols might have open circles attached to the short lines. Digital logic gates help manage multiple inputs, and are used in more complex circuits. [12] X Research source
This is also the symbol for oscillators and resonators. All 3 of these items give off frequencies when actively used in a circuit. Crystals help connect multiple electronic parts. [14] X Research source
The short lines attached to the box shape are known as “pins. ”
Operational amplifiers help combine a negative and positive voltage source into 1 output. You’ll often see “V-in” and “V-out” labels surrounding the triangle symbol, which indicate where the voltage goes in and out. Operational amplifiers have a plus and minus sign on the top and bottom corners on the left side.
There are gaps between all the lines in the battery symbol. Batteries help convert chemical energy into electrical currents. [17] X Research source
Fuses prevent circuits from burning out from too much current. Batteries serve as an extra energy source in the circuit. [19] X Research source
Fuse, hardware, and transformer are all labeled with the first letter of their name. Battery is referred to as “B” or “BT. ”[22] X Research source
For example, if you see “R1,” “R2,” and “R3” in 1 area of your schematic, it means that there are 3 resistors.
For instance, the label 12μF equals 12 microfarad.
For example, if you see a straight horizontal line going between a battery symbol and a switch symbol, you can know that those components are connected.
If you ever feel overwhelmed looking at many overlapping lines, try breaking the schematic into smaller chunks.
Junctions identify where different electrical lines cross over one another. Some of these lines are connected, while other lines just pass one another.
