Magnetic flap to explain in detail the characteristics of the sheet resistance thermometer and manufacturing process

Dc low precise resistance of electrical instruments and meters, including electric meter attached to the outside of the shunt, usually four terminal the sheet resistance of the structure. Figure 5 - 22 is a classic example of sheet resistance. Because they work under the current is bigger, the magnetic flap thermometer will be taken when necessary, oil circulating ventilation or other cooling measures. Sheet resistance because of the use of different requirements, the structure and material is also different. Such as large current shunt or high-power resistance, its working temperature is higher, from type ( 5 a 1) Showed that the temperature, the greater the influence of the temperature coefficient of A second item also, so should pay special attention to its cooling conditions, and should choose mouth is small the resistance of the material. Minimum standard resistance and the heat dissipation problems is not very big, it is main technical requirements of stability, therefore, from the aspects into consideration. XBV magnetic flap | | glass thermometer thermometer floating ball | | glass thermometer thermometer two-color thermometer

2, chip resistor manufacturing XBV magnetic flap | | glass thermometer thermometer floating ball | | glass thermometer thermometer two-color thermometer

resistance material was determined, according to the sheet resistance of the resistance size, resistivity and the thickness of the sheet resistance materials, shape blanking by the regulation, should also be bending method when necessary. Then the resistors with silver brazing or welding method welding to a thick copper terminal ( Or wiring row) On. Due to the small sheet resistance of the resistance, the resistance of the copper terminal larger proportion in the whole chip resistor, so must be carefully and properly selected potential end location. Otherwise, the magnetic flap thermometer due to the interference of terminal resistance stability of the sheet resistance variation, make the temperature coefficient of resistance. Magnetic flap | | glass thermometer thermometer XBV floating ball | | glass thermometer thermometer two-color thermometer

in the process of blanking and bending, resistors inevitably will be affected by stress. When making silver brazing or welding to defend area near that part of the resistance caused by high temperature alloy internal grain mass arranged disorder, and the change of the alloy composition. This is all potential factors which influence the stability of resistance time. So, the sheet resistance must be 500 - after welding - The high temperature of 600 ℃ annealing treatment. High temperature annealing in vacuum or affection of gas, in order to avoid resistance materials react with ambient air. Under the high temperature resistance material trend of distribution of the various components in uniform and cooling, the temperature gradually reduce resistance material, the grain will be rearranged, restore to the original state of equilibrium. Resistance high temperature annealing, must use the special fixture fixed up, which on the one hand, magnetic flap can play a role to prevent the deformation of resistance thermometer, on the other hand to a certain extent had slight deformation resistance can be corrected. The special disaster material, try to high melting point and materials should not contain the spread of the elements. The highest temperature of high temperature annealing depends on silver or copper solder solder melting point. High annealing temperature, annealing time should be shorter. Otherwise, when the grain rearrangement, due to the continued high temperature annealing, which will cause adjacent they pull the new combination, certainly will make the material performance change, mechanical child would also reduce. XBV magnetic flap | | glass thermometer thermometer floating ball | | glass thermometer thermometer double-color

some sheet resistance thermometer is made of multiple parallel resistance material, as shown in figure 5 - 22 a, which requires the resistors with suitable fixture slot into the terminal, and should be fixed well, and then welding. In resistance welding should avoid as far as possible has good resistance welding piece over and over again when heated. For this, can have good resistance welding piece immersed in the water, or use the asbestos board is separated, don't let it directly exposed to the spray gun mouth. To pay attention to the liquidity of solder welding, both to the natural flow, and flow to a certain range, cannot make solder flow rules of port area, otherwise the welding surface will produce porosity and matte, or cause some resistors of short circuit, the resistance tolerance smaller. XBV magnetic flap | | glass thermometer thermometer floating ball | | glass thermometer thermometer two-color thermometer

manufacturing sheet resistance, its value is difficult to control, usually magnetic flap thermometer are doing a little smaller than nominal value, later gradually move. XBV magnetic flap | | glass thermometer thermometer floating ball | | glass thermometer thermometer two-color thermometer

XBV magnetic flap | | glass thermometer thermometer floating ball | | glass thermometer thermometer two-color thermometer

XBV magnetic flap | | glass thermometer thermometer floating ball thermometer | | double color glass thermometer thermometer