Abstract: Provide is a direct liquid type writing-brush pen that is equipped with a valve mechanism; and with which the ink tube is of replaceable cartridge type, and the writing brush tip is always impregnated with an appropriate amount of ink while the ink leakage being suppressed, whereby an excellent feeling of writing can be always given.

Abstract: A multi-layered double-balanced mixer includes first and second transformers formed as first, second and third winding film layers separated by insulating films and stacked on one side of a substrate with first and second input/output electrode pairs connected to opposite ends of the second winding layers of the respective transformers. Diode electrodes of a four diode matrix are connected to one ends of the first and third winding layers. Third input/output electrodes are connected to second ends of the first and third winding layers of the first and second transformers. A film shield covers the first and second transformers and the diode matrix. First and second adjusting stubs are formed as film structures outside of the shield and are connected to a respective input/output electrodes of said first, second and third input/output electrodes for adjusting input impedances of the double-balanced mixer.