Abstract: A transformer includes a core unit that includes an elongated first core part extending in a longitudinal direction and having first and second segments, and an E-shaped second core part including a connecting segment that extends in the longitudinal direction, and three extension segments that extend from the connecting segment in a transverse direction. A central one of the extension segments is disposed in contact with the second segment. The second segment has a size in the transverse direction that gradually decreases along the longitudinal direction away from the first segment. The first core part is movable relative to the second core part from a tunable position to an assembled position for adjusting a position of the second segment relative to the central one of the extension segments so as to vary a size of an effective magnetic flux region defined between the first and second core parts.

Abstract: A transformer includes a bobbin unit, a primary winding, a secondary winding, and a core unit. The bobbin unit has a first winding portion and a second winding portion. The primary winding is wound around the first winding portion of the bobbin unit. The secondary winding is wound around the second winding portion of the bobbin unit, and is coupled electromagnetically to the primary winding. The core unit is mounted to the bobbin unit, and includes a first core part, and a second core part that forms a magnetic circuit path with the first core part. The first core part is movable relative to the second core part from a tunable position to an assembled position for varying a size of an effective magnetic flux region defined between the first core part and the second core part.

Abstract: In a driving device and method for providing an AC driving signal to a load, a first voltage converting unit converts an external AC voltage signal into a DC voltage signal using pulse width modulation in response to a feedback signal that is generated by a summing unit based on a standard voltage signal generated by a voltage detecting unit from the DC voltage signal, and a current detecting signal corresponding to a current flowing through the load and generated by a current detecting unit. A second voltage converting unit converts the DC voltage signal from the first voltage converting unit into the AC driving signal based on an external burst signal, and outputs the AC driving signal to the load.

Abstract: A nail driving gun includes a gun housing, a solenoid mounted in the gun housing and including a coil member and a magnetic core which are magnetically attracted to each other in such a manner that the magnetic core is movable in a frontward direction and the coil member is movable in a rearward direction opposite to the frontward direction when the solenoid is actuated, a striking pin extending from the magnetic core so as to be movable together therewith and so as to expel a nail upon actuation of the solenoid, an urging member for restoring the magnetic core to a normal position, and a shock-absorbing member resiliently abutting against the coil member so as to provide a shock-absorbing effect on the nail driving gun.