Electric Circuit Theory Concept

[anonymoussome]

Why do we take ideal voltage source to have 0 impedance and ideal current source to have infinite impedance.
Please explain mathematically also!

 

[chroot]

An ideal voltage source is a voltage source that does not "sag," or decrease in voltage, no matter how much current we pull from it. An ideal 12V source will always produce 12V, even if you pull a hundred billion amperes of current from it.

A real voltage source, on the other hand, has some finite, non-zero resistance associated with it. A model of a "real" voltage source is an ideal voltage source with a resistor in series with it. As the resistor becomes larger, the voltage source becomes less and less ideal -- if you pull large currents, a large voltage drop appears across the resistor, and the output voltage of the source sags.

If you make the resistor very small, or drive it all the way to zero, the "real" voltage source becomes an ideal voltage source. Thus, an ideal voltage source has zero series resistance, or zero impedance.

The same argument applies to current sources having infinite impedance. Can you make those arguments yourself? Remember that the model of a "real" current source involves an ideal current source with a resistor in parallel.

- Warren

 

[astrokreng]

Electric circuit theory is a fundamental concept in the field of electrical engineering that helps us understand the behavior of electrical circuits. One of the key assumptions in this theory is the concept of ideal voltage and current sources.

An ideal voltage source is a theoretical concept that provides a constant voltage to a circuit, regardless of the current flowing through it. Similarly, an ideal current source is a theoretical concept that supplies a constant current to a circuit, regardless of the voltage across it.

The reason we take ideal voltage sources to have 0 impedance and ideal current sources to have infinite impedance is because it simplifies the analysis of the circuit. In reality, no voltage source has zero impedance and no current source has infinite impedance. However, by assuming these values, we can simplify the circuit equations and make them easier to solve.

Mathematically, we can represent an ideal voltage source as a voltage generator in series with a 0 impedance resistor. This means that the voltage across the source will remain constant regardless of the current flowing through the circuit. Similarly, we can represent an ideal current source as a current generator in parallel with an infinite impedance resistor. This means that the current supplied by the source will remain constant regardless of the voltage across the circuit.

By taking these assumptions, the equations for voltage and current become simpler as the impedance terms cancel out. This allows us to focus on the behavior of the rest of the circuit without being influenced by the ideal sources.

In summary, we take ideal voltage sources to have 0 impedance and ideal current sources to have infinite impedance in electric circuit theory because it simplifies the analysis of the circuit and allows us to focus on the behavior of the rest of the components.