Current Source and Current Sink: Difference

What is Current Source ?

A current source is an electronic component or circuit that actively generates and supplies a constant electric current to a connected load, regardless of variations in the load’s impedance or resistance. It is designed to maintain a consistent current output, acting as a stable source of electrical flow. Current sources are crucial in various applications, such as amplifiers, where a steady current is necessary for accurate signal amplification. The ability to provide a consistent current makes current sources valuable in ensuring predictable and controlled behavior within electronic circuits, contributing to stability and reliability in their operation.

What is Current Sink ?

A current sink is an electronic circuit or component that absorbs or draws in a specified amount of electric current from an external circuit. Unlike a current source, which actively generates and supplies a constant current to a load, a current sink acts as a recipient or absorber of current, providing a pathway for current to flow into it. Current sinks are commonly used in applications where it is necessary to control, absorb, or regulate the current flowing through a circuit. This can be particularly important in scenarios involving inductive loads, where a controlled dissipation of current is needed. In summary, a current sink plays a passive role in a circuit, absorbing and regulating incoming current to maintain stability and control within the overall system.

Difference between Current Source and Current Sink


Sr. No.FeatureCurrent SourceCurrent Sink
1Direction of FlowProvides current to the loadAbsorbs or sinks current from the load
2SymbolArrow pointing out of the sourceArrow pointing into the sink
3NatureActive device supplying currentActive device absorbing current
4Voltage DependencyOutput voltage is less affected by load changesOutput voltage is more affected by load changes
5Load ResistanceIdeally operates with an open loadIdeally operates with a short circuit load
6PurposeUsed to drive a loadUsed to absorb or sink current from a load
7Voltage ComplianceLimited voltage complianceHigher voltage compliance
8Characteristic CurveCurrent remains constant regardless of loadCurrent varies based on load resistance
9Control ElementTypically includes a control element to set the currentMay not have a specific control element for current setting
10ApplicationsCommonly used in active electronic circuits, like amplifiersUtilized in applications where current absorption is required, such as inductive loads
11Output ImpedanceHigh output impedanceLow output impedance


Current Source and Current Sink
Current Source and Current Sink

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