Abstract: The antenna device A1 includes an antenna 1 configured to transmit and/or receive radio waves, and a dielectric elastomer drive element 2 including a dielectric elastomer layer 21 and a pair of electrode layers 22 sandwiching the dielectric elastomer layer 21. The dielectric elastomer drive element is capable of changing an antenna characteristic of the antenna 1. With such a configuration, the antenna device can be made smaller and lighter while improving its antenna characteristics.

Abstract: A method for welding by a magnetically driven arc, which comprises placing two objects of welding in butt formation with a small gap between the end edges thereof to form a welding line; parallelly connecting a first electric circuit comprising the two objects of welding and a cable arranged on the surface side of the two objects of welding and a second electric circuit comprising the two objects of welding and another cable arranged on the back side of the two objects of welding to a welding power source; flowing a welding current through the first and second electric circuits to produce an arc in the small gap; moving the arc along the welding line under the effect of an electromagnetic force in the direction of the welding line, the electromagnetic force being produced by the magnetic flux of magnetizing coils provided near the end edges of the two objects of welding and welding current flowing through the arc; and changing the amount of welding current flowing through the first and second electric circuit

Abstract: An automatic direction finder for automatically finding the arriving direction of electric waves by rotating a goniometer or the like with the use of a stepping motor is described. The stepping motor is controlled by means of a digital circuit using a reversible counter. The polarities of the phase of the output demodulated by a receiving circuit are detected in terms of the antinodes thereof.