What is a Common Ground?
"Common ground" is a term used in electrical systems to describe a reference point for the voltage potential in a circuit. In simple terms, it is a shared connection between two or more electrical components that allows them to operate together in a coordinated way.
In an electrical circuit, there are typically two wires: a "hot" wire that carries electrical current and a "neutral" wire that completes the circuit. The "ground" wire provides an additional path for electrical current to flow back to the source, such as a power outlet or battery, in the event of a fault or short circuit.
Different power supplies have different ground levels. This means that the potential of their ground levels is not equal. Their grounds are floating. This might cause problems when a 0-10 Volt control signal (e.g. coming from a sensor or controller) must be connected to another device (e.g. fan speed controller to define the requested fan speed). If the ground terminals of both devices are not connected, fan speed might vary at random due to the floating grounds of both devices.
To avoid this, a common zero level must be created to correctly compare all signals. To do so, connect the ground terminals of both devices. This will create a common ground level. It will avoid floating of both grounds.
A common ground refers to a single point in the circuit where multiple components, such as switches, lights, and appliances, are connected. This point is typically the ground wire, which is connected to the earth or a grounding rod for safety reasons.
Having a common ground ensures that all components in the circuit share the same voltage reference point, which is important for proper operation and safety. If different components in the circuit have different voltage potentials, it can cause issues such as incorrect readings, interference, or even damage to the components.
In summary, a common ground is a shared reference point for the voltage potential in an electrical circuit, which allows multiple components to operate together safely and efficiently.