Mitsubishi Materials Corporation

Takaaki Itoh

Yoshiyuki Tanaka

Masatoshi Abe

Fujio Ikeda

Takashi Shibayama

Koichi Kurasawa

Naruo Yoshioka

A surge detecting element which is connected to surge invading lines and is composed of a gap type discharge tube and a nonlinear resistor both connected in series with each other and one or more of surge absorbing elements each having an impulse discharge starting voltage higher than an impulse discharge starting voltage of the surge detecting element. A light receiving element is provided for the gap type discharge tube in light receiving relationship therewith for detecting a discharge light thereof, a counter circuit for counting a detected signal from the light receiving element is also provided.

Surge counter

Sealing electrode and surge absorber using the same

A surge absorber including a surge absorbing element for protecting communication equipment from transient surges and a thermal response switch with an automatic restoration function connected in parallel with the surge absorbing element. The inventive surge absorber prevents abnormal and deleterious heating of the surge absorbing element when continuous overvoltages or overcurrents are applied to the surge absorber.

Surge absorber for protection of communication equipment connected to

A surge absorbing element is parallel connected to an electronic device via a pair of communication lines. A normally closed thermal response switch is serially connected between the electronic device and the signal source on the input side of the surge absorbing element. When a surge voltage is instantaneously applied to the communication lines, the thermal response switch remains in the closed position and the surge absorbing element acts to suppress the surge voltage. When an overvoltage or over current is continuously applied to the communication lines, the thermal response pieces of the thermal response switch open and simultaneously release the movable body. Consequently, the electronic device is disconnected from the signal source, thus stopping the continuous overvoltage or overcurrent from flowing to the electronic device and the surge absorbing element. Simultaneously, the reset pin is projected through the casing. After the temperature of the switch decreases, the switch is reset to the closed position by pushing a reset pin which reconnects the electronic device to the communication lines.

Thermal response switch and a surge absorbing circuit using the same

A protective structure for a surge absorber which is composed of the surge absorber, connecting means for connecting the surge absorber to an electronic device and means for protecting the surge absorber as well as the electronic device from fire caused by a continuous overvoltage. The surge absorber protecting means is composed of a first electroconductive spring member which does not deteriorate from heat generated by repeated transient surge voltages to which it might be subjected. This spring member may be connected to a communication line and is movable between a first spring-loaded position wherein it connects the electronic device and the surge absorber to the communication line and a second non-spring loaded condition wherein the connection is broken. Also included are release means for releasing the first member from its first spring-loaded position which release means is activated by heat generated from a continuous overvoltage.

Protection structure for a surge absorber

A microgap type surge absorber comprises a columnar insulator element being covered with a conductive material and provided with a microgap around the center thereof, a pair of conductive caps being fixed on the both ends of the element, first and second electrodes being attached to the both caps, first and second glass tubes adhering to the periphery of the first and second electrodes and surrounding the end parts of the element, and a cylindrical third electrode being held between the both glass tubes and adjacently surrounding the element containing the microgap. The first, second, and third electrodes and glass tubes are charged with inert gas. When a glow discharge started from near the microgap extends to the conductive coating and arrives at the caps, an arc discharge is formed between caps through the third electrode. The third electrode protects the microgap from arc discharge current.

Growing community of inventors

Saitama, Japan

Takaaki Itoh