Abstract: A multi-terminal surge protection device able to absorb surges of either polarity between lines and between a line and ground, in which the difference in operating time between the device elements connected to lines is reduced. A plurality of unipolar surge protection device elements are used which only operate to absorb surges of a specific polarity, and do not exhibit a reverse withstand characteristic upon application of a reverse-polarity voltage. One element is connected to a first line and another element to a second line, while a different element is connected to ground. A semiconductor substrate and second electrode are used that are common to all elements. To prevent lateral interference between elements, at least the element connected to ground is isolated from the line elements.

Abstract: A heat pump apparatus which includes: an accumulator and a sub-accumulator for additionally accommodating the refrigerant arranged between the accumulator and the compressor, in which at least the accumulator or the sub-accumulator is provided with a flow control valve for controlling the refrigerant flow upstream of the accumulator or the sub-accumulator in association with the liquid refrigerant level detected by the level sensor; a bypass line with a bypass valve for bypassing the expansion valve, for controlling the opening of the bypass; and, preferably, a level sensor for sensing the liquid refrigerant level therein; thereby inhibiting the occurrence of foaming of the refrigerant and preventing the refrigerant from entering the compressor, especially at the start-up of the compressor.

Abstract: An air conditioning apparatus for heating and cooling a room, which has a four-way valve to reverse the flow of a refrigerant, thereby switching the operation mode, heating or cooling, and which has a bypass line for bypassing an inside heat-exchanger, a control valve for controlling the flow ratio of the refrigerant passing through the bypass line and the inside heat-exchanger, and a refrigerant-heating element disposed in a line between the control valve and the compressor, thereby, in the defrosting mode, melting the frost formed on endothermic fins without cooling the room and without a liquid return to the suction side of the compressor.

Abstract: A surge absorption device includes fundamentally a first semiconductor region, a second semiconductor region forming a pn junction between itself and the first region, a third region determining the effective thickness of the second region, and a fourth region provided in contact with the first region and forming an injection junction for causing first minority carriers of a kind the same as that of minority carriers in the first region to be injected into the first region. When a depletion layer formed by application of reverse bias across the pn junction reaches the third region, a punch-through region is formed in the second region. In this state, when minority carriers are injected from the fourth region into the first region, the minority carriers are absorbed by the second region to constitute the device current.