Nec Microwave Tube, Ltd.

Netcomsec Co.ltd

Yukihira Nakazato

Junichi Matsuoka

Junichi Kobayashi

Akira Chiba

A first resistor, a second resistor, a transistor, and a third resistor connected in series between a ground potential and an output terminal of a power circuit are provided. In addition, a current-detecting resistor is inserted in series between a high-voltage site and an output terminal of a power circuit that supplies a predetermined direct voltage to the high-voltage site. A differential amplifier controls a current flowing through the transistor so that a potential difference generated between both ends of the third resistor becomes proportional to a potential difference generated between both ends of the current-detecting resistor. At this point, by measuring the voltage of a connection node of the first resistor and the second resistor, the value of a current flowing through the high-voltage site can be calculated from the measured value.

Current measuring circuit

A temperature detection apparatus includes a transformer, a thermostat attached directly to an electrically conductive site of the heating element and has contacts that become short-circuited or come into an open-circuit condition depending on whether or not the temperature of the heating element is equal to or higher than a predetermined value, the contacts being connected to a secondary coil in the transformer, a DC voltage source and a transistor configured to supply required AC power to a primary coil in the transformer, a current detection resistor configured to detect a current flowing through the primary coil in the transformer, and a comparison circuit detecting a voltage generated across the current detection resistor when a current flows through the current detection resistor, the comparison circuit outputting an alarm signal when the current flowing through the primary coil in the transformer exceeds a preset threshold current.

Temperature detection apparatus

A voltage control apparatus used for an electron tube or a power supply apparatus includes a detecting circuit for detecting current flowing through a helix electrode, a voltage-limiting circuit for controlling a potential difference between the helix electrode and the anode electrode based on a predetermined voltage level; and a switch for switching based on an output from the detecting circuit. The switch connects the helix electrode and the anode electrode through the voltage-limiting circuit, or causes a short circuit between the helix electrode and the anode electrode.

Voltage control apparatus, power supply apparatus, electron tube and high-frequency circuit system

The present invention includes a Zener diode connected between a helix electrode and an anode electrode, a transistor that closes or opens a circuit between a cathode and an anode of the Zener diode, a photocoupler for turning ON/OFF the transistor through a phototransistor, a first switch for supplying or cutting off a DC voltage for the photodiode of the photocoupler, a capacitor to which the DC voltage that is to be supplied to the photodiode is applied and a control unit that turns ON the first switch beforehand to apply a DC voltage to the photocoupler and the capacitor and that turns OFF the first switch simultaneously with an application of a helix voltage.

Power supply apparatus and high-frequency circuit system

A power supply apparatus for a traveling-wave tube includes an electrical discharge switch and a first resistor that are serially connected, and that are connected between a cathode electrode and a first collector electrode; N (N denotes a positive integer) arresters that are serially connected, and that are inserted between a ground potential and a connection node of the electrical discharge switch and the first resistor; N second resistors that are inserted between the N arresters and a second collector electrode to an Nth collector electrode and a ground potential, respectively; and an electrical discharge control circuit that turns off the electrical discharge switch at a time of normal operation of the power supply apparatus and turns on the electrical discharge switch when stopping operation of the power supply apparatus.

At the time of restoration of the power supply after a power failure, a voltage higher than that in the normal operation mode is supplied to a heater. After a lapse of a predetermined time, the voltage to be supplied to the heater is switched into the voltage in the normal operation mode while a control signal for stating the operation of an electron tube is output. Alternatively, at the time of power activation, the rate of change of current flowing through a heater is determined for every period of time. When the rate of change becomes equal to or lower than a predetermined threshold, a voltage higher than that in the normal operation mode is supplied to the heater, and after a lapse of a predetermined time, the voltage to be supplied to the heater is switched into the voltage in the normal operation mode while a control signal for stating the operation of the electron tube is output.

Power supply unit, high-frequency circuit system and heater voltage control method

The present invention includes: a transformer; a primary source for supplying an alternating voltage of at least two frequencies to a primary winding of the transformer; and a filter circuit connected to a secondary winding of the transformer and having an attenuation that varies according to the frequency of the alternating voltage, where the frequency of the alternating voltage supplied to the primary winding of the transformer is controlled so that a desired alternating voltage is outputted from the filter circuit connected to the secondary winding of the transformer.

Growing community of inventors

Kanagawa, Japan

Yukihira Nakazato