Capacitors and resistors

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Capacitors and resistors

Postby ahsan19 » Wed Sep 21, 2011 7:43 pm

Hi everyone..

am doing bs electronics and i have a confusion and i hope here i will b able to solve this confusion with your help..

my question is that for designing a circuit how will i choose a capacitor or resistor of certain value, how i will come to know that the capacitor or resistor used in the circuit will be this value268726872687
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Re: Capacitors and resistors

Postby ikalogic » Wed Sep 21, 2011 9:53 pm

Hi,

This question, that i hear a lot, is maybe the one i find the most difficult to answer. Simply because it's not a question that can be answered, it a whole topic.. the answer to that question is achieved via years of study and practice and experience!

So, practical guide to being able -one day- to chose the caps and resistors values!
* Don't stop at what you learn in shcool or university, it's never nearly enough
* try to stay close to practice. Waste a lot of time playing with a resistor and a diode, then with a transistor, try to "feel" the electronics even if you can't make sense of everything. later, when a teacher speaks about electronics, it will fill the gaps and glue the pieces in your head.

That was my methodology to learn electronics. it may not be the best way and may not be suited for you, but that's the best i can offer!

good luck
True wisdom is knowing what you don't know -- Confucius
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Re: Capacitors and resistors

Postby ahsan19 » Thu Sep 22, 2011 8:41 pm

Thank u very much buddy....if u let me know about some method to choose the value of capacitor and resistor for a certain circuit, it will be more helpfull for me.
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Re: Capacitors and resistors

Postby ikalogic » Thu Sep 22, 2011 10:33 pm

U really don't want to believe what i say to you :D

ahsan19 wrote: some method to choose the value of capacitor and resistor
Yes there is a method: Learn electronics!

I am serious, there is no simple method to calculate capacitor and resistors.. it depends on each and every circuit.. it is analog.. is it digital..2687

You have to start from the beginning, learn about volt and current, use a resistor as a current limiter, and then you will see how a resistor value affect the current.. then use 2 resistors of the same value in series to create a voltage divider, and you will see how resistor values can be used to divide voltage..

You asking about a method to chose resistors values, is like someone asking you "how do you know which letters to write in a sentence2687" What would be your answer to that2687 you would say "you have to learn to read and write" and that's exactly what i am trying to tell you!

don't even think that "knowing the capacitor and resistor values" in an easy thing, in fact, many engineers i have come to know still don't know quite well how to carefully choose the values of their components.. it is not and easy skill to learn. it will take time and practice and patience.

Start by looking and simple circuits online.. there are PLENTY of them. then "practice".

I don't know why i spent so much time explaining again what i said in the first place, but trust me this is the best answer you can get in a forum for your question!

Google is your friend, and all the tones of tutorials out there. you can start by this one: http://www.ikalogic.com/beg_1_res_v_c.php
True wisdom is knowing what you don't know -- Confucius
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Re: Capacitors and resistors

Postby ahsan19 » Fri Sep 23, 2011 10:23 pm

I am very thankful to u..u r absolutely right that it is not easy to learn...i asked the same questions to some teachers but they did not answer me...in my last semester i had to design a power supply, my teacher asked me to use a specific capacitor value...i asked him that how we choose this value, he told me to choose anyone of your choice...i was not satisfied with his answer....similarly i had to use aresistor in a circuit, i tried to calculate its value using V=IR, my teacher asked me not to do this, just to chk out different resistors, the one giving me the right output, i should usee...as u know this is not the right method to choose this component...i wanted to know the conditions etc with help of which i can have a better idea what to choose,
I am really very thankful to u.
Regards
Ahsan JAmal
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Re: Capacitors and resistors

Postby ikalogic » Fri Sep 23, 2011 11:07 pm

you're welcome :)

ahsan19 wrote:...in my last semester i had to design a power supply, my teacher asked me to use a specific capacitor value...i asked him that how we choose this value, he told me to choose anyone of your choice...


Okay! that's a good start!

Post this circuit, and i'll tell you what value of capacitor i would use, and explain why i choose so.

waiting for your circuit! :)
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