P
panfilero
- Jan 1, 1970
- 0
Hello,
ok, I'm looking at the datasheet for a 12V voltage regulator...
LM340-12.... here's the datasheet:
http://www.national.com/ds/LM/LM340.pdf
On the first page under Typical Applications theres a schematic
titled: adjustable output regulator... and I can't figure it out,
there's an equation there for Vout, but to me it looks like Vout would
be 12V because it's from the output pin to ground... there's a voltage
divider with a pot, but I don't see how the pot does anythign since
Vout is taken from Vout pin with respect to ground... Woooo but the
ground pin of the voltage regulator is in the middle of the votlage
divider.... so there is 12V across R1.... I'm confused.
Basically I want to use this voltage regulator as an adjustable
voltage out... I was originally just planning to put in a voltage
divider to ground at the Vout pin and have one of the resistors be a
pot and take my voltage out from the middle of the divider...
would my way be ok? or is there a beinifit to folowing the example on
the datasheet?
much thanks!
J.
ok, I'm looking at the datasheet for a 12V voltage regulator...
LM340-12.... here's the datasheet:
http://www.national.com/ds/LM/LM340.pdf
On the first page under Typical Applications theres a schematic
titled: adjustable output regulator... and I can't figure it out,
there's an equation there for Vout, but to me it looks like Vout would
be 12V because it's from the output pin to ground... there's a voltage
divider with a pot, but I don't see how the pot does anythign since
Vout is taken from Vout pin with respect to ground... Woooo but the
ground pin of the voltage regulator is in the middle of the votlage
divider.... so there is 12V across R1.... I'm confused.
Basically I want to use this voltage regulator as an adjustable
voltage out... I was originally just planning to put in a voltage
divider to ground at the Vout pin and have one of the resistors be a
pot and take my voltage out from the middle of the divider...
would my way be ok? or is there a beinifit to folowing the example on
the datasheet?
much thanks!
J.