Hi All,
I'm encountering a strange problem where my voltage regulator works without a certain output cap, but with the cap, it doesn't output the correct voltage.
I've attached a picture of the schematic. I have a really large output tantalum cap (10uF). I've discovered (through a lot of scratching of my head), that the voltage regulator does not work when I have this large cap in. It outputs something like 4.7V instead of 12V like it's supposed to. I also notice that as time goes on, the voltage slowly drops. If anything, I would expect the voltage to slowly rise as the cap gets charged up.
Is the cap too large? The datasheet recommends 0.1uF, but I didn't think a very large cap would cause problems. Or is it because I'm using a tantalum capacitor and has something to do with the ESR?
Thanks.
I'm encountering a strange problem where my voltage regulator works without a certain output cap, but with the cap, it doesn't output the correct voltage.
I've attached a picture of the schematic. I have a really large output tantalum cap (10uF). I've discovered (through a lot of scratching of my head), that the voltage regulator does not work when I have this large cap in. It outputs something like 4.7V instead of 12V like it's supposed to. I also notice that as time goes on, the voltage slowly drops. If anything, I would expect the voltage to slowly rise as the cap gets charged up.
Is the cap too large? The datasheet recommends 0.1uF, but I didn't think a very large cap would cause problems. Or is it because I'm using a tantalum capacitor and has something to do with the ESR?
Thanks.
Attachments
-
39.4 KB Views: 61