Question

What is apparent power in RLC circuit?

Answer 1

In an RLC circuit (which includes a resistor, inductor, and capacitor), **apparent power** is the total power that flows from the source to the circuit. It is a combination of both **real power** (which does actual work, like lighting a bulb or running a motor) and **reactive power** (which does not perform any work but creates and sustains electric and magnetic fields, like in inductors and capacitors).

### Key Points:

- **Apparent power (S)** is measured in **volt-amperes (VA)**, not watts.
- It is the vector sum of **real power (P)** and **reactive power (Q)**.
  
In mathematical terms, apparent power is given by:
  
\[
S = \sqrt{P^2 + Q^2}
\]

Where:
- **P (real power)** is the actual power that is consumed and used in the circuit.
- **Q (reactive power)** is the power stored and released by the inductors and capacitors.
  
#### Why it matters:
- In an RLC circuit, the power is not purely real because the energy stored in inductors and capacitors doesn't contribute to doing useful work. The apparent power represents the total power flowing from the source to the circuit, whether it's actually being used (real power) or just being recycled back and forth (reactive power).
  
### Example:
Imagine you have an AC circuit with a resistor, inductor, and capacitor. The apparent power represents the total power from the source, but not all of it is converted to useful energy. Some of it is "stored" in the inductor and capacitor (as reactive power), which is why you need to consider it separately from the real power.

So, in simple terms, apparent power is like the "total" power you supply to the circuit, which includes both the useful and the non-useful (reactive) parts of the power.