Current Sourcing (拉電流) and Current Sinking（灌電流）

最新推荐文章于 2021-04-18 17:56:12 发布

Cosmomi123456

最新推荐文章于 2021-04-18 17:56:12 发布

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原文链接：http://www.cnblogs.com/youchihwang/p/7199004.html

本文详细解释了电子学中电流源和电流阱的概念，通过电路图直观展示了两种配置的区别。电流源是指设备向负载供电，而电流阱则是指电流从电源经过负载流入设备。文章还提供了具体的实例，如微控制器如何在不同配置下控制LED。

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Current Sourcing and Sinking

Current sourcing and sinking is often mentioned in relation to electronics, digital systems and microcontrollers, but what is current sourcing and what is current sinking?
Current sourcing and sinking refers to the way that an external load is connected to a circuit, system, microcontroller or other electronic device.

Circuit Diagram

The circuit diagram below shows the difference between current sourcing and current sinking.

Current Sourcing (left) and Current Sinking (right)

The load in the circuit diagram is shown as a 1k resistor, but can be any load that draws a current such as an LED and series resistor, the coil of a relay, a light bulb, etc.
The device in the circuit diagram can be any electronic circuit or device such as a microcontroller, FPGA, CPLD, logic circuit, etc.

Current Sourcing

When a load is connected to a device so that the device supplies current to the load (sources current) then the configuration is said to be current sourcing.
An example is a series resistor and LED connected between a microcontroller pin and GND. When the microcontroller pin is switched high (logic 1) then the microcontroller will source current to the load. In this configuration a logic 1 will supply power to the load (switch the LED on) and a logic 0 will switch power to the load off (switch the LED off).

Current Sinking

When a load is connected to a device so that current flows from the power supply through the load and into the device, then the configuration is said to be current sinking. When current flows into the device, it is said to be sinking current.
An example of current sinking is when a series resistor and LED is connected between power (e.g. +5V) and a microcontroller pin. When the microcontroller pin is switched high (logic 1) then the current to the load is switched off. When the microcontroller switches the pin low (logic 0), current flows through the load.