VoltageDivider

Thread Starter

Dr.killjoy

Joined Apr 28, 2013
1,196
I would like help to understanding how voltage dividers work and why the value are being used ???I have been learning how to work out the math and get the results I want but really basic .. But I don't understand how values are figured out and why those particular values are used??? Also how would I look for names in the datasheet as to figuring out what to use for the load rating on the voltage divider ??? I tried the search forum but that seems to be broken lol...


Also what does this mean too
Taking from here
http://forum.allaboutcircuits.com/showthread.php?p=689252#post689252
Any value would work there if you know what I mean.
But higher values would not load the PSU...

Wait...Ur regulator is 78L05...means it can supply 100mA safely. So lower pots will load it too much



Thanks
Jason SR
 

#12

Joined Nov 30, 2010
18,224
Similar question in Homework right now. The first thing you want to consider when making a voltage divider is, "How much current shall I use?"
It depends on the load. Rule of thumb: to make sure the load does not affect the voltage divider by more than 10%, the voltage divider must have 10x the current of the load. For 1% precision, use 100 times the current the load will use, and for .1%, 1000 times the current of the load.

Either that or calculate the current the load will use and design to that load. Not always easy when the load changes. That's why unity gain voltage followers were invented.

Has this gotten you started, finished, or asking more questions?
 
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