Dependent Source and Its Types

• These are the sources that don’t have their own current or voltage instead, their voltages and current are dependent on some other sources(independent sources). The magnitude of these sources is controlled by the dependence factor and the independent source.

Y=kX
Y=kX here,

• Y is the magnitude of the dependent source
• k is the dependency constant
• X is the magnitude of the independent source

There are four possible dependent sources

1. the voltage-controlled voltage source (VCVS)
2. the current-controlled voltage source (CCVS)
3. the voltage-controlled current source (VCCS)
4. an the current-controlled current source (CCCS)

Voltage Controlled Voltage Source (VCVS)-

• here the actual source voltage is controlled by a voltage across an element anywhere else in the same circuit. . VCVS is a type of dependent source where the terminal voltage is dependent on the voltage across some element in that circuit.

Current-Controlled Voltage Source (CCVS)-

• When the actual source voltage is controlled by a current flowing through another branch in the same circuit, it is called CCVS. It is a type of dependent source where a branch current controls the voltage source.

Voltage-Controlled Current Source (VCCS)-

• A source current is dependent or controlled by the changing of voltage elsewhere in the circuit. It is known as VCCS.

Current-Controlled Current Source (CCCS)-

• A current source that depends on a current of some other branch in the same circuit is generally referred to as a Current Controlled Current Source or CCCS.

• In the figure below,
• (a),(b) are independent sources, (c),(d),(e),(f) are the dependent sources

Uses of Dependent Sources

• Dependent sources are used in modeling the behavior of amplifiers.
• A bipolar junction transistor can be modeled as a dependent current source, the magnitude of output current depends on the magnitude of the current fed into its controlling base terminal.
• An operational amplifier can be described as a dependent voltage source, whose output voltage is dependent on the differential input voltage between its input terminal.