Why Different Types of resistors?

[sidharth]

Why Different Types of resistors are there in the market , when one type can solve all the problum's ?

 

[JimB]

Why Different Types of resistors are there in the market , when one type can solve all the problum's ?

Well there you go, that is wrong for a start, one type cannot solve ALL problems.

Consider a 100 ohm resistor, you could have:

a small SMD type, 100mW dissipation limit, but is is small and cheap, non-inductive so it can be used in high frequency circuits without problems.

a large metal cased wire wound resistor, 100 watts dissipation limit, quite expensive, very large, and at more than a few khz there is more reactance than resistance, you can use it at DC and AC power frequencies only.

So tell us, where is this magical universal resistor which can solve all problems?

In your dreams I think.

JimB

 

[burners]

Do you mean as in the % type?
Some are cheaper to produce which makes them cheaper to sell but some circuits will not work correctly or well with the cheaper resistors so then you need to step up to a higher grade resistor.

 

[Gauthamvg]

no dude, % marking is called as tolerance. if a resister marked as 10 ohm +/- 10% means, the true value of the resistor can vary between 9 to 11 ohm. It is not about cheaper or costly. A resistor is chosen of the following terms,
1. the value of the resistor 2. power dissipation rating
The resistors with low current ratings are smaller and the resistance with higher current ratings are bigger.
If you insert low rating resistance in high current path, it will burst out. So one resistance cannot be suitable for all purposes. The guy above you gave an wonderful explanation about the resistors.

 

[Electroenthusiast]

There are many types of resistors, based on its material. Metal alloys, pure metal or metal-oxide films, or carbon (solid or in thin-film form) are some of them. Each one off them are different from each other. There value depends on various parameters like temp, area of application. In certain applications, precision might be required, so high-cost ones are used. So you can say that ' the type of res to be used depends on application and its precision'.

It's insensible to use a high cost resistors for all applications. So, there are many types of resistors.

 

[burners]

no dude, % marking is called as tolerance. if a resister marked as 10 ohm +/- 10% means, the true value of the resistor can vary between 9 to 11 ohm. It is not about cheaper or costly. A resistor is chosen of the following terms,
1. the value of the resistor 2. power dissipation rating
The resistors with low current ratings are smaller and the resistance with higher current ratings are bigger.
If you insert low rating resistance in high current path, it will burst out. So one resistance cannot be suitable for all purposes. The guy above you gave an wonderful explanation about the resistors.

Exactly and the ones with tighter tolerance are generally made with better / more expensive materials. What circuit wold someone find themselves saying "I am going to need a resistor with a real loose tolerance in this spot"?

 

[crutschow]

Exactly and the ones with tighter tolerance are generally made with better / more expensive materials. What circuit wold someone find themselves saying "I am going to need a resistor with a real loose tolerance in this spot"?

You don't deliberately design to require a loose tolerance. But some resistors, such as for use for bias voltages or pull-up, can be a looser tolerance then ones used in a filter, for example. If you aren't concerned about cost, then you would use tight tolerance resistors in all places.

 

[sidharth]

Thanks for great help

i am just before a new bee in electronics and trying to get into it.I have being working as a java programmer from some time and always have a dream to completly understand the software AND HARDWARE so regard to that studying theory's and theory's and constructed some basic kits like LED flasher's smoke alarm ect.. ect... & it's being 1month but even yet i am not able to thing of constructing my own stuff. so what must i do first?

 

[Rbeckett]

Sidharth,
I am still a very new noob too, but I got a breadboard and started swapping out different components in various different proven/working ircuits and observed the over all change in the circuits behaviour. I started by replacing different resistors till I blew up the LED from over driving it and then did the math to determine why it happened. Once I got past blowing up LED's then I went on to observing the circuits when I adjusted the capacity of capacitors and pots and so forth. Sooner or later you will have an "ahh-hah" moment and it will start falling together. Till then, keep building circuits on your breadboard and comparing them with what the math says it should be to what the meter says it is, and try to understand why they are sometimes very different, (because math is perfect and circuits/components arent). Hope this helps.
Bob

PS- Blowing up LED's is fun and a cheap way to understand what happens.....

 

[misterT]

Thanks for great help

i am just before a new bee in electronics and trying to get into it.I have being working as a java programmer from some time and always have a dream to completly understand the software AND HARDWARE so regard to that studying theory's and theory's and constructed some basic kits like LED flasher's smoke alarm ect.. ect... & it's being 1month but even yet i am not able to thing of constructing my own stuff. so what must i do first?

I like that! It is a beautiful thing when software guy understands hardware and hardware guy understands software. When you can do both, you can manage a team of software and hardware guys. So, aim high young padawan!

 

[Gauthamvg]

For understanding the electronics, some people refers a bunch of books to read. please don't do that. First learn the explanations about the components and basics in nut shell. buy an multimeter and few components and practically verify the things you have learned. i this forum i have seen one person's signature i forgot his name but it is absolutely true "The Knowledge in Electronics is directly proportional to the number of components ruined"
If you want to control both Hardware and Software, Embedded system is the beast field for you.

 

[sidharth]

i have created number of circuits ;-) and feeling that every thing is coming under controls. I took a leave for 10 days from my office and Night and day just working on the bench with number of multi meters bred board, card board ,resistors, transistors, LED's, LDR's ,capacitor's, thermistor's, copper wire + coil, bush of wires of different gauges with clips and buzzer's ;-) .

BUT still have so much of math mismatches, and getting tensed about it.


i do understand that 1coulomb is = to the charge of 6.24151x10^(18) electrons
so is it possible to trap only 1 electron any how and can we measure the
charge any how ?

 

[crutschow]

i do understand that 1coulomb is = to the charge of 6.24151x10^(18) electrons
so is it possible to trap only 1 electron any how and can we measure the
charge any how ?

It was done over a hundred years ago in 1909 by Millikan’s oil-drop experiment.

 

[sidharth]

is that necessary to understand the differences between the different subtypes in all type of electrical components like there are number of subtypes in transistor and ect ect..?

 

[crutschow]

is that necessary to understand the differences between the different subtypes in all type of electrical components like there are number of subtypes in transistor and ect ect..?

You should know something about the basic electronic components such as resistors (regular, power), capacitors, (film, ceramic, electrolytic), transistors (NPN bipolar, PNP bipolar, N-MOSFET, P-MOSFET), diodes (small signal, power), inductors and transformers, to get started in electronics.

Wikipedia is a good place to start.

 

[Rbeckett]

The ability to perform a parametric search based on the parameters you consider important will usually yeild a fairly broad selection from the suppliers for you to choose from. Then once presented with this data, you can choose a specific component that addresses your needs and has the most additional features you may wish to add or use to enhance your circuit. So in-depth component knowledge is not required nor in most cases even considered desirable since your knowledge will become dated rather quickly.
Bob

 

[audioguru]

I think I saw a 10% resistor about 48 years ago. I have used inexpensive and accurate 5% resistors ever since.

I have always used a heater as a high power heater and a resistor as a low power resistor. Frequently a low power resistor turned on a high power transistor to dissipate some heat.

 

[nsaspook]

You should know something about the basic electronic components such as resistors (regular, power), capacitors, (film, ceramic, electrolytic), transistors (NPN bipolar, PNP bipolar, N-MOSFET, P-MOSFET), diodes (small signal, power), inductors and transformers, to get started in electronics.

Wikipedia is a good place to start.

The problem is, the more you know, the more you know what you don't know.

 

[KeepItSimpleStupid]

Yep. Things like paper conducts electricity and waving a wire in the air generates a current and even flexing a coaxial cable generates a current. The last one is called the triboelectric effect.

Generally these are not concerns. They were for me.

Sometimes even 2E16 is essentially the same number as 4E16.