The role of controlled sources in the circuit?

1. Controlled source of the circuit symbols and characteristics and independent sources have similarities, that is, the controlled voltage source has the characteristics of the voltage source, the controlled current source has the characteristics of the current source; but they are fundamentally different, the controlled source of the current or voltage by the control of the branch of the current or voltage control, once the control amount of zero, the amount of control is also zero, and the controlled source can not be inspired by its own, that is, when the circuit is not an independent power source There can be no response, so the controlled source is a passive component.

The controlled source is a circuit model, the actual existence of an electrical device, such as transistors, operational amplifiers, transformers, etc., their electrical characteristics can be used to simulate the circuit model containing the controlled source.

2. Circuit analysis of the process of controlled sources

In the process of circuit analysis, the controlled source has a dual nature (power supply characteristics, load characteristics), sometimes need to be handled according to the power supply, and sometimes need to be handled according to the load.

(1) In the use of junction voltage method, mesh method, power supply equivalent transformation, write KCL, KVL equations according to the power supply (the same as independent power supply, the controlled relationship as a supplementary equation).

(2) in the use of the superposition theorem to analyze the circuit, the controlled source can not act alone as a power source, superposition, superposition of only the response generated by the independent power supply, the controlled source of each independent power supply alone should be retained in the corresponding circuit, i.e., the same as the load resistor to be viewed; to find the equivalent circuit of the Davening equivalent circuit, voltammetry to find the equivalent resistance, the independent source to remove, but the controlled source of the same as the resistor to be retained.

These are the same as the load resistor.