# Active and reactive effect in AC circuit

• Engineering
• David331
In summary, the conversation discusses a problem with an AC circuit and the need to compute reactive and active effects for a specific component. The speaker also mentions uncertainty about their calculations and whether the reactive effect can be negative. The other person confirms that a negative reactive power is possible if the load is capacitive, but would be positive if an inductor is used instead. The speaker expresses understanding and gratitude.
David331
Homework Statement
Compute the active and reactive effect that is obtained in the load R2-C3.
Relevant Equations
P=RIe^2; Q=XIe^2
Hi, I am once again asking for help regarding a AC circuit problem. This time I need to compute reactive and active effect for z=R2+C3 in the below circuit. I have already computed u(t) from before so that solves half of the problem. I am unsure if I have done the calculations correct, not much if the number-computations are correct, but if the different formulas all make sense. And if the reactive effect can be negative?

The equations look OK to me.

If the reactive load is capacitive, then the reactive power will be negative. If you substitute an inductor for the capacitor, then the reactive load will be positive.

Okay now I understand. Thanks!

## 1. What is the difference between active and reactive effect in AC circuits?

The active effect in an AC circuit is the energy that is converted into useful work, such as powering a lightbulb or motor. The reactive effect is the energy that is stored and released in the circuit due to the presence of inductors and capacitors. It does not contribute to useful work and can cause distortions in the current and voltage waveforms.

## 2. How are active and reactive effects measured?

The active effect is measured in watts (W), which represents the rate at which energy is being used. The reactive effect is measured in volt-amperes reactive (VAR), which represents the reactive power in the circuit.

## 3. What causes reactive effects in AC circuits?

Reactive effects are caused by the presence of inductors and capacitors in the circuit. These components store energy and release it back into the circuit, causing the reactive effect.

## 4. How do active and reactive effects affect power in AC circuits?

The combination of active and reactive effects determines the total power in an AC circuit, which is measured in volt-amperes (VA). This is known as the apparent power and is calculated using the Pythagorean theorem, where the active power is the horizontal component and the reactive power is the vertical component.

## 5. How can reactive effects be reduced in AC circuits?

Reactive effects can be reduced by using power factor correction techniques, such as adding capacitors to the circuit. This helps to balance out the reactive power and improve the power factor, resulting in a more efficient use of energy.

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