Ideal vs Practical Voltage Sources and Kirchhoff's Laws
English with a size of 2.82 KBIdeal vs. Practical Voltage Sources
| Ideal Voltage Source | Practical Voltage Source |
|---|---|
| Delivers constant voltage regardless of load current. | Terminal voltage decreases as load current increases. |
| Internal resistance is zero. | Internal resistance is small but finite. |
| No voltage drop inside the source. | Voltage drop occurs across internal resistance. |
| Efficiency is 100%. | Efficiency is less than 100%. |
| Short-circuit current is theoretically infinite. | Short-circuit current is limited by internal resistance. |
| Voltage remains constant for all load conditions. | Voltage varies with load conditions. |
| Theoretical concept; does not exist in reality. | Real batteries and generators. |
| Used in theoretical circuit analysis. | Examples: Battery, DC generator, power supply. |
| Perfect regulation (0% voltage regulation). | Imperfect voltage regulation. |
| Internal resistance = 0 Ω. | Internal resistance > 0 Ω. |
| Terminal voltage equals EMF at all times. | Terminal voltage is less than EMF under load. |
| No heat dissipation. | Produces heat due to internal resistance. |
Kirchhoff's Current Law (KCL)
Statement: The algebraic sum of all currents meeting at a junction (node) is zero. The total current entering a node equals the total current leaving it.
Formula: ∑I = 0
Explanation: KCL is based on the law of conservation of charge. Charge is neither created nor destroyed at a junction; therefore, no charge accumulates at a node.
Mathematical Expression: I1 + I2 = I3 + I4 (where I1, I2 are incoming and I3, I4 are outgoing).
Applications of KCL
- Nodal analysis
- Determining unknown currents
- Applied in both DC and AC circuits
Kirchhoff's Voltage Law (KVL)
Statement: The algebraic sum of all voltages around any closed loop in an electrical circuit is zero.
Formula: ∑V = 0
Explanation: KVL is based on the law of conservation of energy. As a charge moves around a closed loop, the energy supplied by sources is consumed by voltage drops across circuit elements. The sum of voltage rises equals the sum of voltage drops.
Mathematical Expression: V - V1 - V2 = 0