In an AC (alternating current) circuit, the power curve is not a sine wave with double the frequency of the voltage. The power curve in an AC circuit is typically a periodic waveform that follows the same frequency as the voltage waveform.
In an ideal AC circuit with a purely resistive load, the power waveform will have the same frequency as the voltage waveform and will also be a sinusoidal waveform. This is because the power is calculated as the product of instantaneous voltage and current, and both voltage and current follow the same sinusoidal pattern.
However, if the AC circuit contains reactive components such as inductors or capacitors, the power waveform may deviate from a simple sinusoidal shape. This is because the reactive components introduce phase shifts between voltage and current, which affects the power calculation.
In such cases, the power curve can become distorted, resulting in a waveform that may not be a pure sine wave. The shape of the power curve will depend on the specific characteristics of the circuit and the relative magnitudes of the resistive and reactive components.
It's worth noting that in a balanced three-phase AC system, the total power is constant over time, but the individual power curves for each phase will still follow the same frequency as the voltage waveforms.
In summary, the power curve in an AC circuit generally follows the same frequency as the voltage waveform and is not typically a sine wave with double the frequency. The shape of the power curve can be influenced by the presence of reactive components in the circuit.