Resistor Types SummaryThen to summa

Resistor Types Summary
Then to summarise, there are many different types of resistor available from low cost, large tolerance, general purpose carbon type resistors through to low tolerance, high cost, precision film resistors as well as high power, wirewound ceramic resistors. A resistor regulates, impedes or sets the flow of current through a particular path or it can impose a voltage reduction in an electrical circuit.

The resistive value of a resistor, its ability to limit current flow is measured in Ohm’s ( Ω ) ranging from less than one Ohm each to many millions of Ohm’s, (Mega-Ohm’s). Resistors can be of a fixed value, for example: 100 Ohms, (100Ω) or variable as in 0 to 100Ω’s.

A resistor will always have the same resistance value no matter what the frequency of the supply from DC to very high frequencies and all resistors have one thing in common, their resistive value in Ohm’s in a circuit will ALWAYS be positive in nature and never negative.

The uses and applications of a resistor within an electrical or electronic circuit are vast and varied with virtually every electronic circuit ever designed using one or more types of resistor. Resistors are commonly used for purposes such as current limiting, providing appropriate control voltages to semiconductor devices, such as bipolar transistors, protecting LEDs or other semiconductor devices from over current damage, as well as adjusting or limiting the frequency response in an audio or filter circuit.

In digital circuits different types of resistors can be used for pulling up or pulling down the voltage at the input pin of a digital logic chip or by controlling a voltage at a point in a circuit by placing two resistors in series to create a voltage divider network, the list is endless!.

In the next tutorial about Resistors, we will look at the different ways of identifying the resistive value of the different types of fixed resistors with the most common method of identification being the use of Colour Codes and colour bands around the body of the resistor.