A circuit (100) for impedance transforming comprises a first port (P1), a second port (P2) and a tapped transformer (110) comprising a first winding (111) and a second winding (112). Each winding comprises a first terminal, a second terminal and a number of taps connected at different positions between the first and second terminals. The circuit (100) further comprises a first programmable capacitor (C1) connected in shunt with the first winding (111) and a second programmable capacitor (C2) connected in shunt with the second winding (112), a first set of switches (S1) connected between the number of taps on the first winding (111) and a terminal of the first port (P1), and a second set of switches (S2) connected between the number of taps on the second winding (112) and a terminal of the second port (P2). The circuit (100) is configured to transform impedance between a first circuit (120) connected to the first port (P1) and a second circuit (130) connected to the second port (P2) by selectively connecting the first circuit (120) to one of the taps on the first winding (111) via the first set of switches (S1) and selectively connecting the second circuit (112) to one of the taps on the second windings (112) via the second set of switches (S2).

An inductive filtering device includes a first toric magnetic core without an air gap formed around a central void; a first electrical conductor formed of turns that are wound around the first magnetic core without passing through the central void, wherein no electrical conductor passes through the central void.

An inductive filtering device includes a first toric magnetic core without an air gap formed around a central void; a first electrical conductor formed of turns that are wound around the first magnetic core without passing through the central void, wherein no electrical conductor passes through the central void.

Disclosed herein is a common mode filter that includes a winding core part and first and second wires wound in a same direction around the winding core part. The first and second wires constitute a first winding block on one endmost side in an axial direction of the winding core part, a second winding block on other endmost side in the axial direction of the winding core part, and a third winding block positioned between the first and second winding blocks. The second winding block is a winding block at an odd-numbered position counted from the first winding block. The first and second wires cross each other in an area between the first and third winding blocks and in an area between the second and third winding blocks.

Disclosed herein is a common mode filter that includes a winding core part and first and second wires wound in a same direction around the winding core part. The first and second wires constitute a first winding block on one endmost side in an axial direction of the winding core part, a second winding block on other endmost side in the axial direction of the winding core part, and a third winding block positioned between the first and second winding blocks. The second winding block is a winding block at an odd-numbered position counted from the first winding block. The first and second wires cross each other in an area between the first and third winding blocks and in an area between the second and third winding blocks.

A balun includes: first wiring that has a first end connected to a first balanced line and a second end connected to a second balanced line; second wiring that has a grounded first end and a second end; third wiring that has a first end connected to the second end of the second wiring and a second end connected to an unbalanced line and is electromagnetically coupled to the second wiring; a first capacitor that has a first end connected to the first end of the third wiring and a grounded second end; and a second capacitor that has a first end connected to the second end of the third wiring and a grounded second end. The first wiring is electromagnetically coupled to at least one of the second wiring and the third wiring.

A filter includes a first capacitor connected in series between a first terminal pair and a second terminal pair, a first inductor connected in parallel with the first capacitor, and a second inductor connected in parallel between the first terminal pair and the second terminal pair. The first inductor and the second inductor are magnetically coupled to each other and are differentially connected to each other.

A filter includes a first capacitor connected in series between a first terminal pair and a second terminal pair, a first inductor connected in parallel with the first capacitor, and a second inductor connected in parallel between the first terminal pair and the second terminal pair. The first inductor and the second inductor are magnetically coupled to each other and are differentially connected to each other.

A noise filter that can be miniaturized is provided. A noise filter includes a terminal fitting, a board, a coil mounted on the board, and an electronic component mounted on the board. The terminal fitting includes a terminal body electrically connected to an external device, a coil connection part electrically connected to the coil through a lead wire, and a board connection part electrically connected to the board. The coil connection part caulks the lead wire.

An inductor device includes a first trace, a second trace, and a double ring inductor. The first trace is disposed at a first area. The second trace is disposed at a second area. The double ring inductor is located at an outside of the first trace and the second trace. The double ring inductor is respectively coupled to the first trace and the second trace in an interlaced manner.