EEVblog Electronics Community Forum
General => General Technical Chat => Topic started by: SirDan on May 09, 2015, 04:40:04 pm
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This may be useful for beginners.
A web based two resistor voltage divider calculator and some basic info.
http://www.voltagedivider.ca/ (http://www.voltagedivider.ca/)
Thanks,
Dan.
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I don't understand this sort of thing. Who can't divide and multiply? ???
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I don't understand this sort of thing. Who can't divide and multiply? ???
Apparently it's not for you.
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You don't even need to divide or multiply, you can just see ratios, and get an approximation or exact result. 1V in, 100kohm top, 200kohm bottom: 2/3rds across bottom resistor, 0.66V out. etc. Takes 5 seconds to do in your head.
The more useful calculators are ones where you can input an output voltage and input voltage and then choose two standard values that get the result within x%. That is hard to do in your head. (Well, for me at least... maybe I'm just a simpleton)
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I don't understand this sort of thing. Who can't divide and multiply? ???
Apparently it's not for you.
but seriously, anyone even remotely into electronics should be able to do a simple voltage divider without the web.
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The formula looks like VOUT = VIN * (R2 / (R1 + R2)).
This is even misleading. Why not say "The formula is VOUT = VIN * (R2 / (R1 + R2))".
As it is written, one may think that " VOUT = VIN * (R2 / (R1 + R2))" is just an approximation of the more complete formula that is used in this web interface.
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I don't understand this sort of thing. Who can't divide and multiply? ???
Apparently it's not for you.
Nor for anyone else intelligent enough to have a need for it...
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The formula looks like VOUT = VIN * (R2 / (R1 + R2)).
This is even misleading. Why not say "The formula is VOUT = VIN * (R2 / (R1 + R2))".
As it is written, one may think that " VOUT = VIN * (R2 / (R1 + R2))" is just an approximation of the more complete formula that is used in this web interface.
Well, it is an approximation... it assumes electric current is a continuous quantitiy, when it's really discrete in nature represented by individual electrons. Below a few hundred attoamperes (10e-18) the error will increase significantly. ::)
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The formula looks like VOUT = VIN * (R2 / (R1 + R2)).
This is even misleading. Why not say "The formula is VOUT = VIN * (R2 / (R1 + R2))".
As it is written, one may think that " VOUT = VIN * (R2 / (R1 + R2))" is just an approximation of the more complete formula that is used in this web interface.
Well, it is an approximation... it assumes electric current is a continuous quantitiy, when it's really discrete in nature represented by individual electrons. Below a few hundred attoamperes (10e-18) the error will increase significantly. ::)
That's known as shot noise and depends on the bandwidth, as much as the current - Amperes is a measure of Coulombs per second.
http://en.wikipedia.org/wiki/Shot_noise (http://en.wikipedia.org/wiki/Shot_noise)
You don't even need to divide or multiply, you can just see ratios, and get an approximation or exact result. 1V in, 100kohm top, 200kohm bottom: 2/3rds across bottom resistor, 0.66V out. etc. Takes 5 seconds to do in your head.
The more useful calculators are ones where you can input an output voltage and input voltage and then choose two standard values that get the result within x%. That is hard to do in your head. (Well, for me at least... maybe I'm just a simpleton)
I agree but there are more silly webpages about such as the charts for converting between picofarads, nanofarads, microfarads etc.
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The formula looks like VOUT = VIN * (R2 / (R1 + R2)).
This is even misleading. Why not say "The formula is VOUT = VIN * (R2 / (R1 + R2))".
As it is written, one may think that " VOUT = VIN * (R2 / (R1 + R2))" is just an approximation of the more complete formula that is used in this web interface.
Well, it is an approximation... it assumes electric current is a continuous quantitiy, when it's really discrete in nature represented by individual electrons. Below a few hundred attoamperes (10e-18) the error will increase significantly. ::)
That's known as shot noise and depends on the bandwidth, as much as the current - Amperes is a measure of Coulombs per second.
http://en.wikipedia.org/wiki/Shot_noise (http://en.wikipedia.org/wiki/Shot_noise)
You don't even need to divide or multiply, you can just see ratios, and get an approximation or exact result. 1V in, 100kohm top, 200kohm bottom: 2/3rds across bottom resistor, 0.66V out. etc. Takes 5 seconds to do in your head.
The more useful calculators are ones where you can input an output voltage and input voltage and then choose two standard values that get the result within x%. That is hard to do in your head. (Well, for me at least... maybe I'm just a simpleton)
I agree but there are more silly webpages about such as the charts for converting between picofarads, nanofarads, microfarads etc.
Such as this one:
http://www.uf-nf-pf.com/index.php (http://www.uf-nf-pf.com/index.php)
;D
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Such as this one:
http://www.uf-nf-pf.com/index.php (http://www.uf-nf-pf.com/index.php)
;D
I didn't even know that this existed. :o
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I once found a website capable of entering a ratio, and it would show you all the possible combinations of E-range resistors to use. Including the error percentage.
Havent found it again since.. forgot to ctrl-d |O
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I once found a website capable of entering a ratio, and it would show you all the possible combinations of E-range resistors to use. Including the error percentage.
Havent found it again since.. forgot to ctrl-d |O
http://jansson.us/resistors.html (http://jansson.us/resistors.html)
http://www.random-science-tools.com/electronics/divider.htm (http://www.random-science-tools.com/electronics/divider.htm)
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I made this one a while ago for my personal use.
http://www.toms-service-manuals.com/Utilities/VoltDivCalc.php (http://www.toms-service-manuals.com/Utilities/VoltDivCalc.php)
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Such as this one:
http://www.uf-nf-pf.com/index.php (http://www.uf-nf-pf.com/index.php)
;D
I didn't even know that this existed. :o
Agreed on the :o! Anyone who needs to use such a thing shouldn't be doing anything with electronics...
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I once found a website capable of entering a ratio, and it would show you all the possible combinations of E-range resistors to use. Including the error percentage.
Havent found it again since.. forgot to ctrl-d |O
http://jansson.us/resistors.html (http://jansson.us/resistors.html)
http://www.random-science-tools.com/electronics/divider.htm (http://www.random-science-tools.com/electronics/divider.htm)
Very useful. But not the same. The internet is very big...
I also use this tool sometimes of you have to stack some smd resistors to get some fancy value.
http://www.qsl.net/in3otd/parallr.html (http://www.qsl.net/in3otd/parallr.html)
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but seriously, anyone even remotely into electronics should be able to do a simple voltage divider without the web.
Using the web is not a bad thing that should be avoided.
I do most of my calculations on the web. Wolfram, Google calculator, unit converters, Linux timestamps, regex, decimal to hex, and even online spreadsheets. That's the beauty of the web.