According to the principle of the spark gaps are divided into unmanaged and managed. Contact information is here: Daniel E Straus. In unmanaged dischargers breakdown occurs at a certain voltage values, depending on the design of the device. In managed – in a certain range of voltages at a pulsed voltage on the gate electrode. The advantages of spark gaps: no heat, virtually instantaneous willingness to work High reliability, small size and weight, Simple design and technology production. Disadvantages spark gaps: For tripping devices to the high value of the transmitted voltage (kV), which results in damage to the equipment being protected.
The intensity of the spark occurring in the while conducting state, often causes interference and leads to a malfunction of nearby electrical equipment. Residual currents lead to disruptions in power and, therefore, unpredictable in the equipment. Parallel Connection of varistors. Varistor Eng. varistor, from vari (able) – ac and (resi) stor – resistor, a semiconductor resistor, the electrical resistance (conductivity), which does not vary linearly and equally under the influence, both positive and negative voltage. For the manufacture of varistors used powdered silicon carbide (semiconductor) and a binder (clay, water glass, paints, resins, etc.) are pressed into shape and sintered it at a temperature of about 1700 C.
Then the sample surface metallized and soldered to its findings. Low-voltage varistors are made on the operating voltage of 3 to 200 V and current of 0,1 mA to 1 A; High-on voltage to 20 kV. Advantages: Varistors have a negative temperature coefficient of resistance, able to withstand considerable electrical overload Easy and cheap, have high reliability, low inertia (limiting the operating frequency to 500 ).
The color has fascinated culture throughout history, every age and every region has produced dyes and pigment depending on available resources. The color has been with us for more than 20,000 years. The evidence survives in cave paintings. The color was widely used by the ancient Egyptians and was considered to have magical and healing, and around this time, 1500 B.C., features painting that made while an art was established quite widely in Crete and Greece with the Egyptians who passed his skills to the Romans. Egypt: The Egyptians used a technique of Temple, bringing together the pigments with water and rubber, glue and egg and applying colors separately, without mixing them among if.
Is not there a number of life-saving? They can be anything that will increase the buoyancy of a person and that you are able to it in good faith (Life preserver, a boat, floating logs, etc.). Cheerfully screaming victim, you are going to help. If you got to swim a drowning, it is necessary to take into account the maximum flow of water, wind, distance to shore etc. Approaching, Try to reassure and encourage forces of vybivshego swimmer. If it failed, and he can control his actions, the swimmer must keep the shoulder saver. If not – deal with it must be hard and ruthlessly to save him and save his life. Brief safety looks like this: swam to the drowning man, you must podnyrnut under him, and took back one of the methods of capture (classic – the hair), transported to shore. To know more about this subject visit