Hello again,
First, thanks to the other members for participating in the first circuit challenge with the LM317. It is interesting to hear others ideas about these circuit problems and how they might be dealt with.
Here again we have an LM317, except this time there are two of them in the same circuit and no, they are not wired in parallel for higher current.
There is a serious flaw in this circuit, doing strictly by the data sheet specs. But this circuit also begs the question, "Why two LM317's in the same circuit if they are not in parallel, what could possibly be the advantage of doing this?"
Assuming we could 'fix' that flaw, there are also a couple drawbacks. One is that the lower LM317 can only be adjusted down to a min of 1.25v and with the upper at a min of 1.25v that means the minimum output voltage is 2.5v not 1.25v like with a single LM317. This may or may not be significant for your personal use, but worth noting. For now however we will assume that we want a min output of something above 2.5v, and for this particular problem the output is adjusted to 14.200 volts.
So can you find the fatal flaw, and if fixed, what would be the reason for using two LM317's instead of just one when they are not intended to be wired in parallel for more output current ?
If you would like to provide your results then please go ahead and just post them. If someone else agrees then they can just post that or more if they like.
Thanks for your interest
First, thanks to the other members for participating in the first circuit challenge with the LM317. It is interesting to hear others ideas about these circuit problems and how they might be dealt with.
Here again we have an LM317, except this time there are two of them in the same circuit and no, they are not wired in parallel for higher current.
There is a serious flaw in this circuit, doing strictly by the data sheet specs. But this circuit also begs the question, "Why two LM317's in the same circuit if they are not in parallel, what could possibly be the advantage of doing this?"
Assuming we could 'fix' that flaw, there are also a couple drawbacks. One is that the lower LM317 can only be adjusted down to a min of 1.25v and with the upper at a min of 1.25v that means the minimum output voltage is 2.5v not 1.25v like with a single LM317. This may or may not be significant for your personal use, but worth noting. For now however we will assume that we want a min output of something above 2.5v, and for this particular problem the output is adjusted to 14.200 volts.
So can you find the fatal flaw, and if fixed, what would be the reason for using two LM317's instead of just one when they are not intended to be wired in parallel for more output current ?
If you would like to provide your results then please go ahead and just post them. If someone else agrees then they can just post that or more if they like.
Thanks for your interest