We all know how much we struggle to read wiring diagrams properly. And I know you are completely at the “no-fault zone” with this. With many electrical symbols, it is very difficult to remember every one of them and using them while solving a circuit diagram.
But there is an easy way to remember them. And believe me when I say its easy. With my graduation in electronics, I have used this trick and was able to solve many circuit diagrams. The trick is: Learn to read electronic symbols. And these symbols are useful also if you are from the electrical stream. With this trick, I was able to read a multimeter, calibrator and most of the electrical tools without hassle.
Yes, you read it right. Let me reveal a little more about this trick. There are many symbols and it is impossible to learn all of them. But you can learn some of the basic ones. And these symbols are useful also if you are from the electrical stream.
Let first learn what are these symbols and how can they make your wiring diagrams study easier. We will learn it step by step so that you will get full advantage of this article and not get confused. So I am starting by definitions:
What are Electrical Symbols or Electronics symbols:
In a very layman term, these are the diagrams assigned for different electrical and electronics tools. You have already seen them in your laboratory machines, daily use electrical appliances or other places.
Let see how Wikipedia defines them:
An electronic symbol is a pictogram used to represent various electrical and electronic devices (such as wires, batteries, resistors, and transistors) in a schematic diagram of an electrical or electronic circuit.
In the above image, some of the electrical symbols are presented. So, basically, these are just the representation of different electronics and electrical devices. And if you have learned these electrical symbols well, you can solve the schematics and will be able to do wiring in your projects easily.
Note: Electrical and Electronics symbols are similar, so don’t get confused.
Now let’s move to another definition.
What are Wiring Diagrams:
A Wiring Diagram is a simple representation of the electrical circuit diagram showing a connection between power and signals between different devices used in that circuit.
According to Wikipedia:
A wiring diagram is a simplified conventional pictorial representation of an electrical circuit. It shows the components of the circuit as simplified shapes, and the power and signal connections between the devices.
Now that you have understood the basic definitions, we can go further and tell you how you can use these electrical symbols in reading wiring diagrams. Let me show you a simple diagram that I have made to make you understand more about the topic.
As you can see this is the simplest diagram with most general components symbols used in the majority of the circuit. It has a resistor, a capacitor, a diode, a bulb, switch and a battery.
Note: Don’t try to solve the above circuit. I made it only to make you understand the symbols. 🙂
I assume that you have already seen the electronics symbols in the above image. And now you have got the point of the discussion. You will get more clear about these once you go through all the symbols I have listed below.
Electrical Symbols list:
I have created a list in which mostly all of the electronics symbols are covered. These are further sub-divided into main devices so that you can learn them easily without any misunderstanding. Let me start with the basic ones:
Wire Symbols: Wire can be represented in 3 ways. If misunderstood, whole circuit study will be a waste of time and you will never get the correct answer. We have only used 2 of them in the above wiring diagrams example. These 3 ways are defined as following:
- Simple Wire: It simply represents a simple wiring between 2 points. Note that there will be no other connection in between these 2 points.
- Connected wires: Whenever, the 2 wires connect at a point, they are called as connected wires and mainly represented by a junction symbol (refer below table).
- Disconnected or Not Connected wires: Sometimes we have to show wire below or above to the other perpendicular wire. The situation is like: The wire is crossing other wire but is not connected. That time to show disconnected wires, this electrical symbol is used.
|Wire type||Representative Symbol|
|Disconnected or Not Connected Wires|
Symbols for Resistor:
The resistor is an electronic component restricts or limit the flow of current and divides the voltage in an electronic circuit. It is one of the most important passive components of an electronic industry because, without these components, active devices cannot process the electrical signals. Its main purpose is to provide a precise quantity of electrical resistance. We have covered a detailed post on Resistors and its type. But we have not covered the symbol table and some special resistors yet, so I am covering it here:
- Variable resistors: A resistor which provides a different value of resistance to the circuit is called variable resistor. This resistor mainly comes with a slider connected to it. It is also called Rheostat.
- Trimmer Resistors: A trimmer or preset is a miniature adjustable electrical component. It is meant to be set correctly when installed in some device, and never seen or adjusted by the device’s user. Trimmers can be variable resistors (potentiometers), variable capacitors, or trimmable inductors.
- Thermistor: Thermistor is a combination of thermal and resistor. It has a negative coefficient resistance and its resistance is dependent on temperature, more so than in standard resistors.
|Resistor Type||Resistor Symbol|
|Simple Resistor (IEEE)|
|Variable Resistor (IEEE)|
|Simple Resistor (IEC)|
|Variable Resistor (IEC)|
A Capacitor is a two-terminal passive device used to store energy in the form of electric charge. It is comprised of two parallel plates separated from each other either by air or by some other insulating device like paper, mica, ceramic etc. The electronics symbol used for this is 2 parallel lines.
For more about types of capacitor, read: Capacitor types. It acts as a short circuit with AC and as an open circuit with DC. Capacitor is the most used electrical component in wiring diagrams after a resistor.
Capacitor is represented in 3 ways depending upon it’s charging nature. These 3 ways are:
- Simple Capacitor: It is a representation of an uncharged capacitor. It means that the switch is off and the capacitor is not charged.
- Polarised capacitor: This symbol is used when we need to show that the capacitor in the circuit is charged i.e. polarised.
- Variable capacitor: This capacitor has different values at different points.
|Capacitor Type||Representative Symbol|
|Simple or Non-Polarised Capacitor (can use any image from these two)|
Symbol for Inductors:
An Inductor is a coil shape device which is used to produce an electromagnetic field. It is a passive 2- terminal electrical component. The more turns, the higher the inductance. The inductance also depends on the shape of the coil, separation of the turns, and many other factors. The electrical symbols for different types of inductors are given in the below table.
|Inductor type||Representative Symbol|
|Iron Core Inductor|
We are sure that these electronic symbols will help you in your studies. We will update the list with more symbols used in wiring diagrams.