| Back to logs list
46483 2008 年 01 月 13 日 01:21 Reading (loading. ..) Comments (0) Category: Personal Diary
Conductive impediment to the current body, said the resistance expressed by the symbol R, in ohms, kilohms, megohms, respectively, with Ω, kΩ, MΩ said.
one, the resistance of the model designation:
domestic resistor model consists of four parts (NA-sensitive resistor)
Part I: Main said, with letters, that the product name. If that resistance R, W, said potentiometer.
Part II: materials, with letters that said what material composition resistors, T-Carbon, H-synthesis of carbon films, S-organic solid, N-inorganic solid, J-metal film, Y-N membrane, C-deposited film, I-glass glaze film, X-wound.
Part III: Classification, general use of digital, said the type of individual with a letter, what type of products. 1 - normal, 2 - normal, 3 - UHF, 4 - high resistance, 5 - high temperature, 6 - Precision, 7 - Precision, 8 - pressure, 9 - Special, G-high-power, T-adjustable.
Part IV: serial number, use the numbers indicate that the different varieties of similar products, to differentiate products and performance indicators Dimensions
example: RT 1 1 type common carbon film resistors a1}
two resistors classification
1, wirewound resistors: Universal wire wound resistor, precision wirewound resistors, high power wire wound resistors, high-frequency wirewound resistor.
2, thin film resistors: carbon film resistors, synthetic carbon film resistors, metal film resistors, metal oxide film resistors, chemical deposition film resistors, glass glaze film resistors , the metal nitride film resistors.
3, solid resistors: inorganic synthesis of solid carbon resistors, organic synthesis, solid carbon resistors.
4, sensitive resistors: varistor,
handbags online cheap, thermistor, photoresistor, force-sensitive resistors, sensing resistors, humidity sensitive resistor. Third, the main characteristic parameters
1, nominal resistance: resistor marked above the resistance.
2, allowing the error: nominal resistance value and the actual difference between the resistance ratio with the percentage of the nominal resistance of said resistance deviation, which indicates the precision resistors.
tolerance level corresponding relations with the precision of the following:? .5% -0.05,?% -0.1 (or 00 ),?%- 0.2 (or 0 ),?%- Ⅰ level ,
designer handbags,? 0% - Ⅱ grade,? 0% - Ⅲ grade
3, Rated power: in the normal atmospheric pressure 90-106.6KPa and the ambient temperature of -55 ℃ ~ +70 ℃ conditions, the resistors long-term maximum power dissipation allowed.
wire wound resistor rated power series (W): 1 / 20, 1 / 8,
mulberry bags, 1 / 4, 1 / 2, 1,2,4,8,10,16 , 25,40,50,75,100,150,250,500
non-wirewound resistor rated power series (W): 1 / 20, 1 / 8,
handbags online, 1 / 4,1 / 2,1,2,5,10,25,50,100
4, Rated voltage: the resistance and rated voltage of the power conversion.
5, maximum working voltage: the maximum continuous operating voltage. Work at low pressure, the maximum operating voltage is low.
6, temperature coefficient: 1 ℃ temperature change caused by each of the relative change in resistance value. The smaller the temperature coefficient, the better the stability of resistance. Resistance increases with increasing temperature for the positive temperature coefficient, and vice versa for the negative temperature coefficient.
7, the aging factor: long-resistor load at rated power, the percentage of relative changes in resistance, it is said that the parameters of longevity resistor.
8, voltage coefficient: the required voltage range, voltage per 1 V change, the relative variation of resistors.
9, noise: generated in the resistor in an irregular voltage fluctuations, including thermal noise and current noise of two parts, thermal noise is due to the conductor of electronic freedom of movement within the irregular , so that any two points on the conductor voltage irregular changes.
four resistor values indicate method
1, straight standard method: The numbers and units marked on the resistor surface resistance, which allows the direct use of error expressed as a percentage, if not note on the bias resistor, then both? 0%.
2, text symbols method: using Arabic numerals and text symbols combination of both, said regular nominal resistance, and its tolerance is also used text symbols. Symbol in front of an integer number of said resistance, said after the first decimal number followed by the resistance and the resistance of the second decimal places.
the text symbol that allows the error text symbols DFGJKM
tolerance? .5%?%?%?%? 0%? 0%
3, digital Method: In the resistor with a nominal value of the three signs that the digital method. Digital left to right, first and second for the RMS, the third for the index, the number of zero, in units of Europe. Deviations usually written symbols.
4, color standard method: use different colored tape or point marked on the resistor surface, the nominal resistance and tolerance. Most of the foreign resistance method using color.
black -0, -1 Brown, -2 Red, -3 Orange, -4 Yellow, -5 Green, -6 Blue, -7 Violet, -8 Gray, -9 White gold -?%, Silver - ? 0%, colorless -? 0%
when the resistance is Victoria, the last part will be for the gold or silver, for the first two digits, the third number for the power, the fourth for the deviation . When the resistance of rings, the last part of the larger distance of the previous City of Victoria. First three digits as the fourth power of the number of bits, the fifth for the deviation.
Five common resistor
1, potentiometer
potentiometer is a mechanical and electrical components, he relies on the brush in the sliding resistance of the body, get into a certain relationship with the brush displacement of the output voltage.
1.1
synthetic carbon potentiometer resistance element is used after grinding the carbon black, graphite, quartz and other materials from coating on the substrate surface, the process is simple, is currently the The most widely potentiometer. Differentiate between characteristics of high strength wear resistance, longer life expectancy. Drawback is that the current noise, nonlinear large tide of resistance,
paul smith wallet, and resistance stability poor.
1.2
organic solid organic solid potentiometer potentiometer potentiometer is a new type, which is heated plastic pressure method, the organic pressure in the insulation resistance of powder within the groove . Solid organic carbon potentiometer potentiometer and compared with the heat resistance, high power, high reliability and good wear resistance advantages. But the temperature coefficient, dynamic noise, poor performance resistant to moisture, complex manufacturing process, the resistance accuracy is poor. In the small, high reliability, high wear resistance of electronic equipment and the AC and DC circuit for regulating voltage and current.
1.3 potentiometer
uranium metal glass screen printing method in accordance with certain graphics, the metal glass ceramic uranium resistance paste coated substrate, the high temperature sintering. Features are: wide range of resistance, heat resistance, strong overload, resistant to moisture, wear and so very good, the potentiometer is promising varieties, drawback is that a large contact resistance and current noise.
1.4
potentiometer winding is wound potentiometer Kang copper or nickel-chromium alloy wire as the resistance of the body, and put it around the insulation made of the skeleton. Wound potentiometer is characterized by small contact resistance, high accuracy, temperature coefficient, the drawback is poor resolution, low resistance, high-frequency characteristics of difference. Mainly used as divider, rheostat, equipment and work in zero points.
1.5
metal film potentiometers potentiometer resistance metal film body can be alloy film, metal oxide film, metal foil, respectively, formed. Characteristics differentiate high power, high temperature, low temperature coefficient, dynamic noise, smooth and good.
1.6
conductive plastic potentiometer with a special process to DAP (C thin phthalate esters) resistor paste cover the insulation body, the heat resistance of polymer into a film,
alexa mulberry, or DAP resistance to pressure in the insulation powder thermoplastic matrix to form the solid body cavity as the resistor body. Characteristics: smooth, good, excellent wear resistance differentiate force, long life, dynamic noise, high reliability, resistance to chemical corrosion. For space equipment, missiles, aircraft radar antenna servo system.
1.7
with switch potentiometer switch potentiometer rotating, push-pull switch potentiometer, push, switch potentiometers
1.8
preset potentiometers preset potentiometer in the circuit, once the debugging is good, adjust the position with wax seal, under normal circumstances, no regulation.
1.9 Slide potentiometer
change by way of direct sliding resistance.
1.10
double potentiometer shaft is different and the coaxial double double potentiometer potentiometer
1.11 non-contact potentiometer
; non-contact potentiometer eliminates mechanical contact, long life, high reliability, sub photoelectric potentiometer, magnetic pots and so on.
2, solid carbon resistors
strong conductive particles with carbonaceous material, fillers and binders into a physical resistor.
characteristics: low price, but the resistance error, the noise voltage is large, poor stability, there is less use.
3, wound resistors with high resistance alloy
skeleton made of insulated wire wound on the outside of the glaze coated with heat-insulating layer or insulating paint.
winding resistance with lower temperature coefficient of resistance, high precision, good stability, heat resistance to corrosion, mainly to do with precision high-power resistors, high frequency performance drawback is poor, a large time constant.
4, thin film resistors
evaporation method with a certain resistance material deposited on the surface made of insulating material. Mainly as follows:
4.1
the crystalline carbon film resistor deposited on the carbon skeleton made of ceramic rods. Carbon film resistors, low cost, stable performance, wide range of resistance, temperature coefficient and low voltage coefficient, is the most widely used resistors.
4.2 metal film resistors.
vacuum evaporation method to alloy material deposited on the surface of ceramic rod frame.
metal film resistor carbon film resistor than high precision, stability, noise, temperature coefficient. In the instrumentation and communications equipment are widely used.
4.3
metal oxide film resistor deposited on an insulating layer of metal oxide rods. Oxide because of its own that is so high temperature stability, thermal shock, load capability.
4.4 Synthesis of the conductive composite film resistance
suspension derived coating on the substrate and, therefore, called the film resistance.
presented because of its granular structure of the conductive layer, so its noise, precision is low, mainly with his manufacturing high voltage, high impedance, small resistor.
5, uranium metal glass resistor
uranium metal powder and glass powder mixed with screen printing printed on the substrate.
resistant to moisture, temperature, temperature coefficient is small, mainly used in thick film circuit.
6, Chip Resistor SMT
uranium metallic glass sheet resistance is a form of resistance, the resistance of his body is highly reliable, ruthenium series of glass through high temperature sintering of uranium material into the electrode paste with silver palladium alloy. Small size, high accuracy, good stability, because of its components for the sheet, so high-frequency performance.
7, sensitive resistors
device characteristics is sensitive to resistance to temperature, voltage, humidity, light, gas, magnetic field, the role of pressure-sensitive resistor.
sensitive resistor symbol is the symbol of resistance in general add a slash mark in the sensitive side type of resistance, such as: t. v and so on.
7.1, varistors
are silicon carbide and zinc oxide varistor, zinc oxide has more good features.
7.2, humidity resistance
by the sense of wet layer, electrode, insulator composition, humidity resistance including lithium chloride humidity resistance, humidity resistance of carbon, oxides humidity resistance. Lithium chloride humidity resistance and resistance decreases with increased humidity and disadvantages of the test range of small, poor repeatability characteristics, affected by temperature. Disadvantage of low carbon humidity resistance low sensitivity, resistance affected by temperature, the aging characteristics, and less use.
oxide humidity resistance properties of superior long-term use, the temperature effect is small, the resistance changes linearly with the humidity. A tin oxide, nickel ferrite, and other materials.
7.3, photosensitive photosensitive resistance is resistance
conductivity changes with the change of light within their means of electronic components, when a substance by the light, the carrier concentration increased to increases the conductivity, this is the photoconductive effect.
7.4, using some of the semiconductor gas absorption resistance
some redox reactions occurred after the gas is made, the main component of metal oxides, the main varieties are: metal-oxide gas Min resistance, mixed oxide gas sensing resistors, ceramic sensing resistor and so on.
7.5, force-sensitive resistors
force-sensitive resistor is a resistance changes with pressure resistance, known as the piezo resistors abroad. The so-called pressure resistance effect that the resistivity of semiconductor materials with the changes of mechanical stress effects. Torque meter can be made of semiconductor microphones, pressure sensors. The main varieties are force-sensitive resistor silicon, selenium, tellurium co-Jin Limin resistors, relatively speaking, alloy resistors with higher sensitivity.
UGG Boots Article - 1042 - Young children Cardy UGG Boots ...
Linear Mode
