Abstract: A method for manufacturing an apparatus includes the steps of forming a plurality of circuit regions on a single master print circuit board, soldering one or more interconnection leads upon corresponding pad electrodes of the foregoing circuit regions, in a state that the plurality of circuit regions are connected with each other mechanically to form the master print circuit board, and dividing the master print circuit board into individual printed circuit boards each corresponding to one of the circuit regions on the master print circuit board.

Abstract: An optical apparatus has a protecting tube made of rubber or resin, a ferrule holder in which a ferrule connected with an optical fiber cable passing through a cable inserting hole of the protecting cap is held, a lens holder fixed to the ferrule holder, a package holder fixed to the lens holder, a protecting tube in which the ferrule holder, the lens holder and the package holder are tightly set, and a flange placed on one end of the protecting tube. An optical axis of the optical fiber cable, an optical axis of a lens held in the lens holder and an optical axis of an optical semiconductor device which is packed in a device package held in the package holder agree with a common optical axis of the optical apparatus. The protecting tube is formed by rolling up a metal plate, and the protecting tube and the flange are integrally formed.

Abstract: A method for manufacturing an apparatus includes the steps of forming a plurality of circuit regions on a single master print circuit board, soldering one or more interconnection leads upon corresponding pad electrodes of the foregoing circuit regions, in a state that the plurality of circuit regions are connected with each other mechanically to form the master print circuit board, and dividing the master print circuit board into individual printed circuit boards each corresponding to one of the circuit regions on the master print circuit board.

Abstract: A diode limiter including a signal line connects an input terminal to which a high power electric pulse signal is applied and an output terminal connected to a receiver. A PIN diode conducts when the high power electric pulse signal is applied thereto and provides a low impedance connection of the signal line to ground. A directional coupler extracts a part of the high power electric pulse signal out of the signal line. A detector diode is inserted in the return direct current path of the PIN diode, a resistor is inserted into the path including the directional coupler, and a means is provided for applying the voltage generated in the resistor to the PIN diode.

Abstract: In a semiconductor device which has an air tight metal package containing a high frequency wave range circuit element and which has a waveguide-coaxial line transformation structure, a metal terminal for the waveguide-coaxial line is air-tightly attached directly in a hole of a base of the metal package with a dielectric spacer, usually by glass fusion, whereby the thickness of the base may be reduced and attachment of the terminal to the base is simplified.

Abstract: A power supply circuit including a voltage stabilizing circuit and a voltage changing circuit responsive to an external control signal. The power supply circuit operates in one of two voltage-level changing modes. One mode changes the voltage level from a first stabilized output voltage to a second stabilized output voltage and the other mode cuts off or restores a stabilized output voltage.