Hello all, I know this has been hashed and rehashed many times, but I still am having trouble with my question, so I am resurrecting a very old thread to hopefully get some better answers since I am very new at understanding circuits and such.
I have searched through the forum and the internet, and have found various circuits and explanations of the LM339 TL431 and so on:
http://forum.allaboutcircuits.com/attachment.php?attachmentid=26570&d=1295139211, http://forum.allaboutcircuits.com/attachment.php?attachmentid=26655&d=1295412736 and http://forum.allaboutcircuits.com/archive/index.php/t-25238.html
Now all of these are great, I understand the diagrams and such, but here is where I run into problems, all of these are for lower voltages than what I am requiring.
I have a battery pack that is 26.4V, I would like to have a high intensity LED light-up once the voltage hits 20V or some other predetermined voltage. Here is another twist, I really do not want to use a pot!
After going through these forums and reading about these circuits, it would be great for someone to just say, here is the circuit, but what I am asking for are the equations (remember I am just a DIY novice on all of this so be gentle with the equations!) on how to determine resistor and zener sizes when dealing with different voltages with a diagram such as this http://www.eleccircuit.com/low-voltage-battery-monitor-by-lm339/ and if there is another way to get around using a pot by determining the actual resistor number through an equation.
Have enjoyed reading and learning through other responses, so if someone would be so kind as to help me out with this that would be great!
Thanks,
Jim
I have searched through the forum and the internet, and have found various circuits and explanations of the LM339 TL431 and so on:
http://forum.allaboutcircuits.com/attachment.php?attachmentid=26570&d=1295139211, http://forum.allaboutcircuits.com/attachment.php?attachmentid=26655&d=1295412736 and http://forum.allaboutcircuits.com/archive/index.php/t-25238.html
Now all of these are great, I understand the diagrams and such, but here is where I run into problems, all of these are for lower voltages than what I am requiring.
I have a battery pack that is 26.4V, I would like to have a high intensity LED light-up once the voltage hits 20V or some other predetermined voltage. Here is another twist, I really do not want to use a pot!
After going through these forums and reading about these circuits, it would be great for someone to just say, here is the circuit, but what I am asking for are the equations (remember I am just a DIY novice on all of this so be gentle with the equations!) on how to determine resistor and zener sizes when dealing with different voltages with a diagram such as this http://www.eleccircuit.com/low-voltage-battery-monitor-by-lm339/ and if there is another way to get around using a pot by determining the actual resistor number through an equation.
Have enjoyed reading and learning through other responses, so if someone would be so kind as to help me out with this that would be great!
Thanks,
Jim