Resistors (results: 2008)

Resistors - their functions and parameters

Resistors play a key role in electrical circuits. Firstly, they provide protection, and secondly, are responsible for various functionalities of devices. In our offer, single resistors as well as sets of them can be found. We have products made of various materials. However one thing connects them all, that is the quality, which is guaranteed by the reputation of a manufacturer. Now, let's focus on what resistors are and what they are used for. What are the colours of resistors and what do they mean? This and many more questions will be addressed in the text below. 

What is a resistor?

Basically, resistors are really diverse devices which are distinguished by their construction and parameters. Nevertheless, the task of a resistor is always to limit the flow of the current, that is decreasing the electrical current and voltage. It is worth noting that when it comes to resistors, their application, as a rule, applies to limiting the current and not stopping it completely. However, some resistors in relevant conditions can in fact lead to termination of the current flow in an electrical circuit. 

Classic resistor consist of a resistive material and an insulating layer. Key role in a flow regulation plays of course the resistive material which is mostly responsible for individual parameters of a resistor. What materials are responsible for the resistance? That could be carbon, some kinds of metal, rarely special foil. In our offer you will find resistors with every kind of a resistive material. We offer qualitative wirewound models from, among others, Bochen company, as well as carbon models from TCO company and many more. 

Although the general function that resistor serves in the electrical circuit is always the same, precise actions are various. As a potentiometer it can be used to slightly limit or increase the power in order to e.g. turn down the volume of a television or radio. However as a LED resistor, it can be used to regulate the light intensity, and also prevents the diode from damage caused by too high electrical current and voltage.

How to choose a resistor according to their colours?

We briefly explained what resistor is used for, however the question is how to choose the appropriate one according to the given application?  The key aspect is to learn about parameters of the device. This is the base on which one has to choose a resistor. We offer a wide selection of resistors with diverse parameters in order to meet the expectations of every customer. However we do realise that this may cause problems when it comes to the selection of a relevant device. It is worth noticing here that there are different colours of resistors. More specifically, not of the whole devices but bands that appear on them. The number of bands ranges from 3 to 6, depending on the type of a resistor. Colours of resistors correspond to their values:

• Resistance
• Multiplication
• Tolerance
• Temperature coefficient of resistance

The most important indicator is without a doubt the resistance. It defines what resistance against the current a given electronic or electrical resistor has. Both too low or too high electrical current and voltage are a problem. When it's too low, the device is not able to function properly. In case of too high values on the other hand, the resistor may be damaged or may result in a malfunction of the device where it is mounted. Choosing an individual device or a set of resistors, one has to take into consideration the tolerance, that is the highest possible deviation of the real value of resistance from the nominal value. Another parameter is the temperature coefficient of resistance, referring to resistance changes affected by the temperature change.

What are the symbols of resistors?

When it comes to resistors, they have both schematic symbols and letter codes. In schematic symbols, the resistor is referred to as a horizontally placed rectangle with two horizontal lines coming from the centre of the left and right side. On the other hand, the code letter for the resistor is “R”. It is worth pointing out that symbols of resistors are always the same, regardless of the parameters and type of a resistor. Should you have any doubts, we encourage you to contact us. We will eagerly help to choose an optimal resistor.