Inside a Resistor
Resistors are made in several different ways, and although they just look like blobs on a wire, they are quite interesting.
Thermistors
Effect of Temperature on Resistance:
Temperature affects the value of the resistance. Pure metals such as copper and aluminum resistant high temperature because the temperature increase caused power electronics and so increase the free speed, therefore, increasingly colliding with the metal ions are becoming more and more resistance to the passage of these electronics.
Altobeiran can change the resistance temperature change by a factor called the coefficient of thermal resistance that has the symbol α.
Is the amount of change in the value of the conductor resistance of 1 ohm when I change the temperature one degree Celsius
Temperature affects the value of the resistance. Pure metals such as copper and aluminum resistant high temperature because the temperature increase caused power electronics and so increase the free speed, therefore, increasingly colliding with the metal ions are becoming more and more resistance to the passage of these electronics.
Altobeiran can change the resistance temperature change by a factor called the coefficient of thermal resistance that has the symbol α.
Is the amount of change in the value of the conductor resistance of 1 ohm when I change the temperature one degree Celsius
There are two types of thermistors:
1 / resistance of the positive thermal coefficient (PTC)A resistance increase in value of increasing the temperature, certain types of semiconductors when the temperature rises in 1950 to 150 m e. e., it increases its resistance suddenly.
Has been to take advantage of this property in the manufacture of thermal resistors with the positive coefficient of thermal resistance (PTC).
2 / resistance with a negative thermal coefficient (NTC):A resistance is worth less with increasing temperature and are made of carbon, semiconductors and called these materials Balmouselat hot any materials that increase the conductivity hight temperature shows the curve change resistance of these materials with temperature, and take the temperature, which is running the equipment to resist thermal coefficient Negative thermal resistance term starts from the 1950 percentage, up to 400 m and e. about using these types of resistors in the electrical measuring devices and transducers used to measure small temperature
Thermistor Characteristics
photo resistor
It is made of semi-conductor material and ceramic cover and placed inside a glass.
LDR and change resistance when exposed to the beam of light, reducing the value of resistance from a number of Mega ohms to several kilo ohms or less.
It is used for circuits that rely on light in operation, such as lighting columns the streets at night.
LDR and change resistance when exposed to the beam of light, reducing the value of resistance from a number of Mega ohms to several kilo ohms or less.
It is used for circuits that rely on light in operation, such as lighting columns the streets at night.
This is called resistance, light resistance / photoresistor or photocell
Variable Resistor / VR
Possible through these resistors to obtain different values of resistors depending on the party put the slider to these resistors
Is the resistance can change their value ranging from zero to maximum value.
For example: when we say that the value of resistance of 10 kilo ohms This means that the value ranging from zero to up to 10 kilo ohms. We see this resistance in audio devices such as: radio, when we want to control the sound, it is through a variable resistance
Changing the form of resistance:
Has several forms, as shown
Has several forms, as shown
Carbon film resistors
- This is the most general purpose, cheap resistor. Usually the tolerance of the resistance value is ±5%. Power ratings of 1/8W, 1/4W and 1/2W are frequently used.
Carbon film resistors have a disadvantage; they tend to be electrically noisy. Metal film resistors are recommended for use in analog circuits. However, I have never experienced any problems with this noise.
The physical size of the different resistors are as follows.
 From the top of the photograph 1/8W 1/4W 1/2W |
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This resistor is called a Single-In-Line(SIL) resistor network. It is made with many resistors of the same value, all in one package. One side of each resistor is connected with one side of all the other resistors inside. One example of its use would be to control the current in a circuit powering many light emitting diodes (LEDs).
In the photograph on the left, 8 resistors are housed in the package. Each of the leads on the package is one resistor. The ninth lead on the left side is the common lead. The face value of the resistance is printed. ( It depends on the supplier. )
Some resistor networks have a "4S" printed on the top of the resistor network. The 4S indicates that the package contains 4 independent resistors that are not wired together inside. The housing has eight leads instead of nine. The internal wiring of these typical resistor networks has been illustrated below. The size (black part) of the resistor network which I have is as follows: For the type with 9 leads, the thickness is 1.8 mm, the height 5mm, and the width 23 mm. For the types with 8 component leads, the thickness is 1.8 mm, the height 5 mm, and the width 20 mm.
Metal film resistors
- Metal film resistors are used when a higher tolerance (more accurate value) is needed. They are much more accurate in value than carbon film resistors. They have about ±0.05% tolerance. They have about ±0.05% tolerance. I don't use any high tolerance resistors in my circuits. Resistors that are about ±1% are more than sufficient. Ni-Cr (Nichrome) seems to be used for the material of resistor. The metal film resistor is used for bridge circuits, filter circuits, and low-noise analog signal circuits.
 From the top of the photograph 1/8W (tolerance ±1%) 1/4W (tolerance ±1%) 1W (tolerance ±5%) 2W (tolerance ±5%) |
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Resistors connected (Series / Parallel)
Often requires connecting several resistors in the circuit and be connected in two ways, either series or in parallel
Resistors in Series
When connecting the resistors in a Series We find that the positive terminal of the resistance related with the negative terminal of the resistance of the second To complete the circle Here the electric current passing in the circuit and In resistance Equal And the total voltage on each resistance Equal to the voltage of the battery In other words, the voltage on each different from the other resistance
Resistors in Parallel
When you connect resistors in parallel We find that the positive terminal of the battery positive connection with the parties of the resistance and the negative terminal of the battery connection with the parties of the negative resistors and Here, the voltage difference On both ends of each resistance is equal to battery voltage And the total electric current passing in each resistance Equal to the electrical output of the batteryIn other words, the electrical resistance in each pass-through is different from the other
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electrical resistance
Is a physical property, mean obstruction article For the passage of electric charges during which And resistance occurs when electrons hit the atoms moving in article And release energy in form of heat / Change electrical energy into heat
The definition of electrical resistance
Is a property Connector For the passage of electric current Which result in a rise in temperature
And measured the electrical resistance by ohms And symbolized by the letter Ω
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