What will be the total resistance of ideal voltage source?

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SUMMARY

The total resistance of a circuit with an ideal voltage source is effectively zero ohms when considering the source's internal resistance. An ideal voltage source maintains a constant voltage regardless of the load, which means its internal resistance is zero. When calculating total resistance, one must clarify whether the components are in series or parallel, as this affects the measurement. The discussion emphasizes the importance of defining the measurement points and understanding the distinction between DC and AC analysis.

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  • Understanding of ideal voltage sources
  • Knowledge of Thevenin's theorem
  • Familiarity with AC and DC circuit analysis
  • Basic concepts of resistance and impedance
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  • Study Thevenin equivalent circuits in detail
  • Learn about AC circuit analysis techniques
  • Explore the concept of equivalent impedance in circuits
  • Review the principles of voltage measurement across circuit components
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Electrical engineers, circuit designers, students studying electronics, and anyone interested in understanding the behavior of ideal voltage sources in circuits.

Sampad Saha
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If we connect a single resistor in the circuit of ideal voltage source then what'll be its total resistance? ? Isn't it zero? As shown in image .so is it possible that the total resistance of a circuit is 0 Although it has 5ohm resistor!?
IMG_20150403_091252.jpg
 
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An ideal voltage source can power any load you throw at it while continuing to maintain a constant voltage. So its resistance remains zero.
 
NascentOxygen said:
An ideal voltage source can power any load you throw at it while continuing to maintain a constant voltage. So its resistance remains zero.
yaa..Sir, I know that its internal resistance must be zero. But what's about total resistance of the circuit? Is it also be zero?
 
If that wasn't the answer to your question, then you weren't asking the right question. The voltmeter is across the source, so regardless of what else is going on, its voltage is held fixed by that source.

The effective resistance of a circuit comprising an ideal voltage source in parallel with anything is zero ohms.
 
Sampad Saha said:
yaa..Sir, I know that its internal resistance must be zero. But what's about total resistance of the circuit? Is it also be zero?
I think maybe you are confused about the calculating the equivalent impedance (resistance in your case) of a circuit.
There are 2 circuits to draw.
The first circuit is the Thevenin equivalent of the circuit. In your case, it would be an ideal voltage source with a 0 Ohm series resistance. This circuit is used to calculate DC values mostly. So in this case if the voltage is 5 V and the load resistor is 5 Ohms, the DC current is 1 Amp.
The second circuit is the equivalent impedance (or resistance in your case) of the circuit. This circuit is calculated by replacing ideal voltage sources with a wire (I.e., shorted). In your case, this circuit becomes just a resistor of 0 Ohms (Note that there is no voltage source in this circuit). The 5 Ohm load is still across the terminals. Normally this circuit is used for AC analysis. Suppose you connect a 110 VAC supply with a 110 Ohm resistor in series across the 5 Ohm resistor. What is the AC voltage across the 5 Ohm resistor? By superposition, the voltage across the terminals is 5 Volts DC (calculated from the first circuit) plus 0 VAC (calculated from the second circuit). Normally the equivalent impedance is not zero and there is an AC component across the terminals. By using the equivalent circuit impedance, the task of calculating signal levels is made easier.
Hope this helps.
 
Sampad Saha said:
If we connect a single resistor in the circuit of ideal voltage source then what'll be its total resistance

A question well stated is half answered.
Above question is not well stated. You introduced a term that you did not first define.

Just what do you mean by "total resistance" ?
The "total" of all the resistances in your circuit is 5 ohms + Rvoltmeter.

Are you considering your voltage source and resistor as being in series or being in parallel when you measure "total resistance" ??

You must define between what two points you intend to measure said "total resistance" .
 

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