GND is a fundamental term used in electronics. In fact, you’ll see it written on almost all modern devices that use electricity. Many people don’t know the meaning of GND, so they ask, “What is GND in electronics?” Understanding the basics of GND is crucial because it completes the circuit and makes devices work.
Without GND, most electronic devices would fail to operate or behave unpredictably. Some devices, such as a sensor, can show incorrect readings if their GND is misconnected or loose. If you are too new to the GND concept, worry not! In this guide, I will discuss everything about GND, including its types, working, and importance. So, let’s get started.
What is GND in Electronics?
Let’s begin with the definition of GND.
GND stands for ground. It is a reference point in an electronic circuit. It is usually set as 0 volts. All other voltages in the circuit are measured relative to this point (GND). GND also provides a return path for electric current, enabling proper flow. Simply put, without a GND, the circuit will be incomplete, and electronics will not work correctly.
An energy source such as a battery produces electricity. This electricity must come back to the source. If it comes back, it will complete the circuit, so that device will work. However, if it does not come back, the circuit would be incomplete. As a result, the device won’t work. GND is the path that returns electricity back to the power source so that circuits are completed.
Secondly, GND is also a common point where all parts of the circuit connect. If parts of the circuit are not connected to the same point, they will not sense the applied voltage. This confusion will prevent the circuit’s components from working correctly. When every component connects to the same GND, they all agree on what 0 volts means.
It is noteworthy that GND is not always connected to the Earth or soil. For example, in small devices like smartphones, the GND is actually the negative side of the power source. Even though it is called “ground,” its main job is to keep voltage levels clear and stable so that all internal circuit parts work efficiently. So, you should not get confused because of its name “ground”.
Why is GND Usually 0 Volts?
GND is usually set to 0 volts. Why? That’s because it makes electronics simple to understand for beginners. This helps prevent measuring voltage at many points. So, the engineers choose a single common point and set it to 0 volts (GND). As I said earlier the GND is considered a reference point. So, all other voltages in the circuit are measured in comparison to GND. But note that GND is 0 volts; it does not mean it has no current.
It just serves as a reference point for measuring all other voltages. When you measure the height of mountains, you use sea level (the reference point or starting point). Right? A place can be above or below sea level. However, sea level is set to zero for easier measurement. Similarly, GND is selected as the reference voltage. We say “GND is 0,” and then we measure everything else above or below it.
Why is GND Important in Electronics?
In the section below, I will explain the importance of GND. This will help you understand why modern manufacturers use GND in electronics.
- Provides a Reference Voltage: As I said above, GND provides the circuit with a reference point for measuring voltage. When we say a circuit has 5 volts or 3 volts, it means the voltage is measured relative to GND. Without this reference point, voltage values would not make sense. Even without GND, PCB manufacturing is not possible.
- Completes the Electrical Circuit: As you know, when current passes through a circuit, it must come back to work properly. So, in an electronic circuit, the GND provides a path for current to return. When the current returns, it completes the circuit, and the entire circuit works properly.
- Ensures Stable Operation: GND helps maintain the voltage levels and keep it controlled. Not only this, but good GND connections also reduce noise in electronics and prevent the part from behaving abnormally. As a result, the circuit operates efficiently, ensuring a smooth overall electronic operation.
- Maintains Safety: In many systems, GND helps protect people and devices. How? Actually, when extra or unwanted electricity appears, GND safely directs it away, preventing damage or shock. This way, GND maintains the safety of the entire circuit and the people.
How Does GND Work in a Circuit?
The working principle of these GND is straightforward. They act as a return path for current and a common connection point for all the components in the circuit. As mentioned above, electricity always needs a complete loop to flow. For example, in a circuit, electricity flows from the power source. It passes through various components of the circuit and returns to its power source. So, GND is the path that brings the current back to its power source.
Now, GND also serves as a common connection point (reference point) for all components in the circuit. Every part of the circuit, like resistors, LEDs, sensors, or chips, uses the same GND. All voltages of these parts in the circuit are measured relative to GND. For example, if a microcontroller pin shows 5 volts, it means it is 5 volts above the GND level. This keeps the voltage values clear and consistent across all components.
Types of GND in Electronics
GND in electronics is not always the same. Depending on the purpose and PCB capabilities, you will find different types of GND in electronics. So let’s dive in and explore some common GND types used in electronics.
1- Signal GND
I consider Signal ground (signal GND) as one of the most sensitive GND types. This type is used for low-power signals in a circuit. Audio, sensor readings, and communication data are examples of low-power signals. Signal GND’s primary function is to act as a reference point for these weak signals. This ensures that devices can comprehend the proper voltage levels. The readings or signals could be erratic and noisy in the absence of a signal ground. The reason is that they (signals) become distorted when they combine with other high-power currents.
2- Power GND
Another type of GND you often see in electronics is a power ground. It is used to handle high-current parts of a circuit. Power GND basically carries a large amount of current back safely to the power source. With a power GND, high-current devices are protected from voltage drops and circuit instability. You will find the power ground in the robot or motor circuit in an electronic device.
Remember, the motor requires a lot of current. So, the chances of short circuit increase if the current is not grounded. The motor is connected to the power GND for this reason. It guarantees that the remaining electronics, such as controllers or sensors, are unaffected. Engineers typically keep power ground separate from signal ground. This is because the signal ground is very sensitive, and it measures very low voltage. If noisy power-ground current flows through the same ground, the signals can be distorted.
3- Analog GND
Analog ground is the GND type used in analog circuits in electronics. These circuits handle continuous signals such as sound, light, temperature, or voltage levels. Analog GND thus serves as a reliable reference point for analog signals in these circuits. Suppose you use a microcontroller that has a sensor that detects temperature or light. This sensor is basically connected to the analog GND.
These sensors measure temperature or light and send that information to the computer. Right? If the sensor is connected to the GND of the computer’s digital parts, it can cause problems. The digital parts switch on and off quickly. As a result, the sensor’s tiny signals may become mixed up or noisy due to the digital parts’ signals. This would make the readings wrong. But analog ground ensures that the sensor readings remain accurate, no matter even if the digital parts of the circuit switch rapidly.
4- Digital GND
Digital ground is a ground reference used in digital circuits. These circuits primarily handle signals that rapidly switch between 0s and 1s. The digital ground serves as a return path for digital current and a reference point for the digital components to operate correctly. For example, on a microcontroller board, the digital ground handles the return current from LEDs and buttons. As buttons are switched, a digital ground prevents high-speed signals from disturbing lower-power signals.
5- Earth GND
Earth ground is a typical type of GND that is physically connected to the Earth. The primary purpose of this GND is safety. How? Sometimes, an unwanted current flows through a circuit, causing a short circuit. This short circuit can be dangerous to people and the nearby environment. But an Earth GND provides a path for this unwanted current to the ground. For example, in your home wiring, the third pin of the plug is connected to earth ground. If any mishap occurs inside the appliance, electricity flows safely into the Earth instead of shocking you.
GND Symbols in Electronics You Must Know
In electronic circuits, GND is often represented by special symbols. You will find these symbols in the manuals or on diagrams or circuit boards. Basically, these symbols help you know where the ground connection is. For more clarity, let’s discuss and understand the common GND symbols you often come across.
Three Horizontal Lines (Stacked): This is the most common GND symbol you will see. It looks like three horizontal lines of decreasing width, stacked one on top of the other. It tells you about a reference point for voltage in a circuit. It is often used in circuit diagrams and schematics.
- Downward-Pointing Triangle: As the name states, it is a GND symbol with a triangle pointing downwards. It indicates that the component of the PCB or wire connects to ground. You will commonly see it in digital and analog circuit diagrams.
- “GND” Label: Sometimes manufacturers simply label GND on circuit boards with “GND.” This is a direct, simple way for beginners to show that a terminal is connected to ground.
- Earth Ground Symbol: This is the symbol that looks like a line with three shorter lines tilting downward. This symbol simply represents a physical connection to the Earth.
GND is the same as Earth Ground: A Common Misconception!
Many beginners think that GND (ground) and Earth ground are the same. However, this is a misconception and is not always true. As I said above, in electronics, GND usually refers to the reference point in a circuit from which all voltages are measured. It is used to complete the circuit and allow current to flow. However, it is not necessary, as it is physically connected to the Earth.
For example, in a battery-powered device, its negative side is GND. It is 0 volts in the circuit, but it is not connected to Earth. On the flip side, earth ground is always connected to the Earth. Its purpose is to ensure the safety of large, complex electronic devices. Earth ground ensures that unwanted current flows into the Earth. This prevents the current from reaching the surrounding area and the device.
Conclusion
Let’s conclude – GND is the most crucial concept in electronics. However, from the name, it feels technical to beginners. That’s why, in this article, I have discussed everything you need to know about GND. GND stands for ground, which serves as a reference for measuring voltages in a circuit. It also provides the return path for the current to complete the loop.
So we can say that without GND, no circuit can work properly. Moreover, there are also various types of GND to fit different electronic devices. Each GND ensures that specific parts of a circuit work correctly and reliably. To make things easy for you, manufacturers label the GND with some symbols. These symbols indicate where the ground connection is. In short, understanding all this information about GND helps you design any circuit board with confidence.