Showing posts with label Resistors. Show all posts
Showing posts with label Resistors. Show all posts

The Construction of a Carbon Film Resistor

Our recent discussion was all about the Characteristics of Resistors and on this post, we will be dealing about it's constructions. We are going to learn the materials inside this small electronic component and understand more how it works. To refresh your memory, we have discussed that the primary function of a Resistor is to provide resistance limiting the flow of electrons which depends on the component's specification.

There are several different types of Resistors coming out from the market and perhaps there are even new types that we are not yet aware about. Anyway, the most common type is the Fixed Value Resistors. If you are a student taking-up a course in the field of electronics, you will be making use of this type of Resistor in your projects. They will teach you how to read its value either through the Multi-Meter device or Color Coding procedure.

So what are the material composition of a Resistor?

Inside the Resistor is a small Ceramic Rod. On the manufacturing process, complicated machines are able to insert thin films of carbons into the rods. The next process is to place the Resistive Coating around the ceramic rod through spiral rotation. The machine performing such delicate procedure is programmed to make sure that both ends of the rods will have the correct value.


You can easily find Carbon Film Resistors on the market. They come with cheap prices and there are several fixed values that are available for you to buy. However, these values ranges from ±10% or ±5% or the "Nominal Value".

Metal Oxide and Metal Film are made in the same process but the main difference is that they have higher accuracy in value which ranges from ±2% or ±1% of their nominal values. Although, the accuracy in terms of the nominal values does not have any effect on simple circuits thus complicated circuits are the once that rely on using these types of resistors.

Resistor

If you want complete accuracy then the Wirewound Resistor is best recommended for your project. Such type of accurate resistors are made by winding-up thin wires around the ceramic rod. The application for this type of component are used in complicated reading devices such as Oscillator, Multi-Meters, and etc... The best part of using Wirewound Resistor's advantage is that it can pass a large amount of current without resulting into overheating. Thus, circuits that require high currents such as Power Supplies do use this type of Resistor.

The Characteristics of Resistors

Components that are considered as “Passive” means that they do not rely on power and such component are the resistor, capacitor, and inductors. There’s more other type of passive components but the focus of this discussion is all about resistors.

Circuit designing is a complicated task where you are puzzled on defining the right value of resistors that are to be used.

Resistors are available on the market with a cheap price and there are thousand of them with different characteristics and specification.

The function of a resistor on the circuit is to provide resistance where it limits the flow of electrons depending on the specification of the component. For this reason, it can be used through different applications. Other than its ability to provide resistance, it is can also limit the flow of current, adjust voltage levels and etc…


Resistors

The following are the properties of resistors: Tolerance, voltage rating, power rating, temperature rating, frequency response, and temperature coefficient.

Let’s explain the properties of a resistor one at a time starting from the tolerance. This is the value of the resistor or the range on where it can vary. The common parameters are 1%, 5% and 10%. You may find that there are other resistors that their tolerance falls below the one percent value and they are categorized as Precision type of resistors.

The voltage rating of a certain circuit can be safely adjusted or drop through the application of a resistance. Power rating is simply the amount of power consumed by the resistor. It is highly suggested to use a resistor with a power rating value over than what is exactly required.

Temperature rating is the range of the device where it can operates normally. Exceeding the limit will cause the resistor to be damaged or burnt. Finally, the frequency response is simply the change in impedance. The changes on the value of impedance depend on the function of the circuit.

Buying a resistor on the market will require you to provide them the exact amount of value as discussed on the previous paragraphs. However, before even trying to purchase them you need to make sure that they are particularly needed on your project.

Summary of the Characteristics of Resistors


Here are the following list of basic characteristics of resistors;

1. Resistance
2. Power
3. Temperature Coefficient
4. Noise
5. Inductance