Information about Fixed and Variable Resistors

Author: hostarticles | Posted: 12.05.2012

An electrical circuit consists of a number of elements, which allow the electric current to pass through them as required by the electronic device. There are cases when the steady flow of electric current inside the circuit needs to be controlled. This opposition to the normal flow of electric current is known as resistance. In order to control or resist the flow of current in an electrical circuit, special electrical elements called resistors are used. Both fixed resistors and variable resistors can be used as required by different devices for controlling current flow.

It should be noted that not all kinds of materials possess the same resistance power. There are a number of factors that determine the resistance of a material. These include the type of material it is made from, the cross-sectional area and length of the material and the temperature of the material. The resistors, apart from reducing the flow of electric current through an electrical circuit, also serve other purposes. In amplifier circuits, resistors can be used to offer feedback networks. They can be used as voltage dividers. Resistors help in causing voltage drop when electric current passes through them.

An electrical resistor is made up of a resistive material that is put in between the two metal end caps present in the resistor. This resistive component of a resistor is commonly made from three substances namely wire wound, metal oxide and carbon composition. wire wound resistors are very expensive because coils of non-inductive wire are used to make them. They can be used in dissipating a lot of power. Though carbon resistors are very cheap, they possess high tolerance ratings. Their value of resistance also changes with time and temperature. However, a better accuracy and stability can be obtained from metal oxide resistors, which are also quite expensive.

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