Active filter

Power factor correction circuit that cancels harmonic components of the current by switching a small passive element (coil) with an active element in order to improve the power factor. Unlike passive filters, another type of power factor correction circuit, it does not have disadvantages such as being "bulky," having a narrow input current and input voltage range, being unable to achieve a power factor of 0.9 or higher, or being difficult to design. Because it can be made compact, it has become the mainstream power factor correction circuit.