This type of resistor is commonly used for making printed circuit boards. This type of resistor produces accurate resistance as the whole process of its making can be controlled. Thick films are also produced in the same manner as a thin film.
But they also have some additional compounds like glass and also a screen printing liquid. Both of them vary in their temperature ranges as well as prices. Thin films are more expensive than thick films. This type of resistor is made by coating with nickel chromium [NiCr]. The process of making this resistor is similar to that of thin film resistors. The difference will be in the compounds used. This is the most unique type of resistor which is used for current sensing.
It has four terminals and is used in the milliohms and microohms range. Though they are used for measuring small currents, if the current is allowed to pass through a shunt mechanism, they can be used for measuring high currents as well. Through this mechanism the current is measured with accordance to the voltage drop across it. The shunt mechanism consists of two brass blocks. Inbetween them are strips of low temperature co-efficient of resistance alloys.
Large bolts threaded into the blocks make the current connections. There are also other types of resistors like lead arrangement resistors, grid resistors and so on. There are also variable resistors like the tapped resistors, metal oxide varistor MOV and strain gauge.
To know more click on the following links. The value of the resistance is found out by colour coding. The resistors have a band of colours shown in their outer covering. Here are the steps to determine the value of the resistor. Take a look at the colours and their associated numbers given below. Though resistors can cause wastage of electricity, it has a lot of advantages and applications in our daily life. Hi, test out the various circuits in this website.
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Example like the capacitor, resistor transistor ic ans so on. I want to know their behavior when u connect them to a tester and is either working of not how will u know and even if is working but not working to the best expected how will i know, pls pls pls help me with this. Microelectronics has set into the electronics field and the surface mounted devices SMDs. Semi conductor Resistors also have come. It would have been appropriate if you would have dealt with all those types too, including trim-pots and presets.
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We measure electrical power in Watts. In a resistive circuit, power is calculated by squaring the current and multiplying that value by the resistance. Because resistors impede the flow of current, they generate heat.
If the resistor operates within its power rating, the heat is harmlessly dissipated into the surrounding environment. But, if we exceed the wattage rating, the resistor cannot dissipate the excess heat, and its temperature rises. The resistor will fail, usually by acting as a fuse and breaking the circuit. If the resistor is used in a high temperature environment, its power rating must be lowered, or "derated. The resistance of all materials changes as their temperature changes.
If the temperature is lowered, resistance typically declines. In fact, if cooled sufficiently, the material becomes a "superconductor" with no significant resistance. Increasing the temperature typically increases resistance. The temperature coefficient of resistance TCR of wire or a resistor relates the change in resistance to the change in temperature.
The temperature coefficient of resistance, then, tells you how much the resistance changes ppm if the temperature changes one degree Centigrade. Sometimes, we measure temperature in degrees Fahrenheit. But today, degrees Centigrade is more common and acceptable.
Special wire alloys are formulated to have special temperature coefficients. These, and other alloys allow us to "tailor" the resistor to desired characteristics in applications where temperatures change. In the same application, a resistor made with Evenohm wire would increase to only ohms. There is another quantity that is similar to resistance.
It is called "reactance. Reactance only occurs in electrical or electronic circuits if the current flow is changing rapidly.
It is usually important in "alternating current" AC circuits where the current periodically changes direction and amplitude at some rate called "frequency.
Reactance occurs because all circuit elements have "inductance" and "capacitance. However, the inductance of wire wound resistors can be critical! All conductors have some inductance.
When the conductor is coiled, as it usually is in wire wound resistors, this inductance becomes larger. In AC circuits, inductance causes "inductive reactance. Inductive reactance increases as the frequency of the alternating current increases. For example, a resistor might have enough inductance to create one ohm of reactance at a frequency of 60 Hz cycles per second. BUT, by using resistors, you can design your circuit to have the currents and voltages that you want to have in your circuit.
Then I tried using only the battery and the LED, and it still worked! But after a few seconds, the LED turned really hot. So hot I almost burned my fingers. Then I started to realize that maybe there was something to these resistors.
Read more about using a current limiting resistor. Learning to work with resistors is important in electronics.
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