What Are the Usual Symbols Used on Schematic Plates?

Schematic PlatesDifferent kinds of schematic plates or diagrams use different kinds of symbols. There are symbols that are meant to be used for electronic circuitry and there are some that are used for automotive purposes. There are also symbols that are used to show people how factories are put together and some that show how one machine is connected to another. In short, with all these different kinds of schematics, it is but natural that there be a wealth of symbols used for these things.

To be able to effectively understand and use a schematic, a person has to have some knowledge regarding the symbols used on these plates and diagrams. For a person to understand at first glance what a schematic is for, the need to memorize a number of these symbols and their meanings. To help you get an idea as to what kinds of symbols are used on these schematics, here are a few of them and what each one means.



Connected – these two crossing lines with a dot in the middle shows that two wires are attached to each other electrically and are conducting. The dot in the intersection is what tells people that the wires are connected.



Unconnected – these two crossing lines with a curve in the middle of one shows that these are not connected. While these two wires are crossing, the curve indicates that no connection is made between these two.


Switch – this symbol shows that there is a device in the circuit that can be broken to stop the current from flowing, hence the 45 degree angled line above another line across from it.

Resistor – this symbol consists of a jagged line between two short straight lines. This is used to show that there is a resistor in the circuitry and that this is used to resist the flow of the current in the diagram. This is often used to show an area with a limited current or where voltage is divided.

Fuse – this can actually be drawn a few ways, with this symbol being one of the choices. This shows that the circuitry has a fuse in it, which is often used as a safeguard against surges. This particular symbol is used to portray a safety device that breaks when currents are too strong.

Ground – this is used to portray 0 volts, or a ground, which is often used for two things. It can be used to symbolize a return path that is used by the current to divert back to the power supply, or it can be used to symbolize a reference point that is used to compare all other voltages in the circuit.

Circuit Breaker – this symbol is used to show a circuit breaker in the system and indicates that the location has a device that opens when it detects a surge in the current that flows through this.

These are but a few of the usual symbols you will see being used on schematic plates. Other symbols that you will find include those that indicate alternating currents, DC power source, a lamp, fixed and variable capacitors and many more. Other commonly used symbols that you will find being used in these diagrams also include those that are used to show inductors and transformers, voltmeter and many more.

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