What is a Load Current?
A Load Current is the amount of electrical current that is passed from a power supply to the device or component receiving the power. Most power supply are only capable of providing certain amounts of power before they become too hot or short out. This means the current load capabilities of a power supply and the load requirements of the item being used should be taken into consideration before any item is connected to a power supply. Any item being connected to a power supply may be damaged if the load that is provided by the power supply is greater than the load the item is capable of handling. When this aspect is not taken into consideration and an item is connected to a power supply that provides much greater load than the item is capable of handling, the item may overheat and become damaged.
In most cases, an energy source isn’t measured directly in current load terms. Instead, power supplies are usually measured in terms of voltage and can even be referred to as voltage sources in many cases. These types of voltage sources send a constant current to whatever item is connected to them.
Voltage and current power systems work effectively as long as the amount of electrical current that is required from the power supply is within the power supply’s current load capabilities. When a device which requires power needs to pull more current from the power supply than the source is able to provide, a short circuit typically occurs. This means the power supply is unable to provide the sufficient amount of current to effectively power the device.
It can be defined as
- Full load current: the maximum current that an electrical machine can operate.
- Rated Current: the current rated on the nameplate of an electrical machine.
- Nominal Current: is generally mentioned in the specification documents that is normally the same value as the rated one.
- No-Load Current: the value of the current required just to turn the motor shaft with nothing connected.
With simple circuits and simple signal sources, it is usually obvious how different circuits and loads affect signal behavior at a circuit’s output. With more complex circuits, and with wideband analog signals, it is not always obvious how signals are affected by the circuit itself, or how current loads affect signal behavior. While you could work out these aspects of signal behavior by hand, not everyone is a mathematician, and you’ll need some tools to speed up analysis of complex circuits.
When you have access to a powerful simulation engine in your schematic design software in PCB design stage, you can quickly examine how load impedance affects signal behavior in the frequency domain vs. time domain. Some simple simulations will show you how a load and its upstream circuit modifies a signal.