Resistors

 Resistors

Resistors, (R) are the most fundamental and commonly used of all the electronic components. There are many different Types of Resistor available for the electronics constructor to choose from, from very small surface mount chip resistors up to large wire-wound power resistors.

The principal job of a resistor within an electrical or electronic circuit is to “resist” or to set the flow of electrons (current) through them by using the type of conductive material from which they are composed. Resistors can also be connected together in two different ways. Those are series and parallel combinations to form resistor networks which can act as voltage droppers or current limiters within a circuit.

Types of resistors

There are thousands of different types of Resistor and are produced in a variety of forms because their particular characteristics and accuracy suit certain areas of application, such as High Stability, High Voltage, High Current etc, or are used as general purpose resistors where their characteristics are less of a problem.

Types of resistors

•  Carbon resistors

The Carbon Resistor is a low to medium type power resistor which has a low inductance making them ideal for high frequency applications but they can also suffer from noise and stability when hot. Carbon resistors are generally prefixed with a “CR” notation (eg,CR10kΩ ) and are available in E6 ( ± 20% tolerance (accuracy) ), E12 ( ± 10% tolerance) and E24 ( ± 5% tolerance) packages with power ratings from 0.125 or 1/4 of a Watt up to 5 Watts.

• Film type resistors

The generic term “Film Resistor” consist of Metal Film, Carbon Film and Metal Oxide Film resistor types, which are generally made by depositing pure metals, such as nickel, or an oxide film, such as tin-oxide, onto an insulating ceramic rod or substrate.

• Wire wound type resistors

Another type of resistor, called a Wire wound Resistor, is made by winding a thin metal alloy wire (Nichrome) or similar wire onto an insulating ceramic former in the form of a spiral helix similar to the film resistor above.