Abstract: A surge protective device includes a first electrode terminal and a second electrode terminal; n gap units, connected in series between the first electrode terminal and the second electrode terminal sequentially, where a common terminal is formed between adjacent gap units; k first trigger circuits, the k first trigger circuits each include a first terminal connected to one of the common terminals, and a second terminal connected to the second electrode terminal; and m second trigger circuits, the m second trigger circuits each include a first terminal connected to one of the common terminals, and a second terminal connected to the first electrode terminal, where any one of the common terminals is connected only to either the first terminal of one of the first trigger circuits or the first terminal of one of the second trigger circuits.

Abstract: The invention relates to a high-safety surge protective device which comprises a casing, at least one overvoltage protection component inside the casing, a release unit used to separate the overvoltage protection component from the AC or DC circuit or the equipment, an arc suppressing apparatus used to suppress electric arc generated while separating the overvoltage protection component from the AC or DC circuit or the equipment, and a box, Wherein: the release unit comprises a compression spring, a metal dome, a slide and a soft conductor; the arc suppressing apparatus comprises an arc chute assembly, a first arc striking sheet, a second arc striking sheet, a turning block and a torsional spring.

Abstract: An efficient optical radiation detector for lightning or other light signals such as pulses, bursts, flashes, and steady fluctuations. A silicon photodiode (or similar light-sensitive silicon device) is arranged to receive light signals (infrared, visible, ultraviolet, broadband, etc.) of interest. The photodiode is connected across the primary winding of a properly-designed transformer. The transformer-coupled photodiode circuit gives AC coupling, photodiode bias, voltage gain, and several other desirable detector characteristics. Light fluctuations on the photodiode produce variations of photocurrent in the transformer primary circuit which, in turn, induce current in the secondary winding and circuit of the transformer. The current induced in the secondary circuit of the transformer is used to do useful work (such as energize an audible alarm, increment a counter, latch a relay, etc.