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David Nebenzahl
Guest
Wed Mar 10, 2010 7:35 pm
On 3/10/2010 9:48 AM Arfa Daily spake thus:
Quote:
On 9 Mar, 00:20, David Nebenzahl <nob...@but.us.chickens> wrote:
I'm wondering if running a 3-volt device (cheap digital camera) on 3.3
volts will hurt it. Yeah, I coulda gotten a 3-volt wall wart to run it,
but it was expen$ive. The 3.3V regulator I got was a little more than a
buck. Haven't tried it yet.
There's nothing wrong with the diode route to drop the voltage by a
(reasonably) constant amount, but just use a Schottky type, which will have
a forward voltage drop of around 0.3 to 0.4v - or just about what you're
looking for ...
Can they handle the current (~ 1A)?
In any case, I'm reasonably sure that I can run the camera on the 3.3
volts without fear of damage.
--
You were wrong, and I'm man enough to admit it.
- a Usenet "apology"
Arfa Daily
Guest
Thu Mar 11, 2010 3:20 am
"David Nebenzahl" <nobody_at_but.us.chickens> wrote in message
news:4b97e503$0$2357$822641b3_at_news.adtechcomputers.com...
Quote:
On 3/10/2010 9:48 AM Arfa Daily spake thus:
On 9 Mar, 00:20, David Nebenzahl <nob...@but.us.chickens> wrote:
I'm wondering if running a 3-volt device (cheap digital camera) on 3.3
volts will hurt it. Yeah, I coulda gotten a 3-volt wall wart to run
it,
but it was expen$ive. The 3.3V regulator I got was a little more than
a
buck. Haven't tried it yet.
There's nothing wrong with the diode route to drop the voltage by a
(reasonably) constant amount, but just use a Schottky type, which will
have a forward voltage drop of around 0.3 to 0.4v - or just about what
you're looking for ...
Can they handle the current (~ 1A)?
Of course they can. All switchmode power supplies, including those that
provide many amps of output, use such diodes as their secondary-side
rectifiers ...
Arfa
Franc Zabkar
Guest
Thu Mar 11, 2010 4:45 am
On Mon, 08 Mar 2010 15:20:07 -0800, David Nebenzahl
<nobody_at_but.us.chickens> put finger to keyboard and composed:
Quote:
I'm wondering if running a 3-volt device (cheap digital camera) on 3.3
volts will hurt it. Yeah, I coulda gotten a 3-volt wall wart to run it,
but it was expen$ive. The 3.3V regulator I got was a little more than a
buck. Haven't tried it yet.
Unless the 3.3V regulator is a fixed type, it may be possible to bring
it down to 3.0V by changing a feedback resistor. Can we see a photo of
the PCB?
- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.
David Nebenzahl
Guest
Thu Mar 11, 2010 6:38 am
On 3/10/2010 7:45 PM Franc Zabkar spake thus:
Quote:
On Mon, 08 Mar 2010 15:20:07 -0800, David Nebenzahl
nobody_at_but.us.chickens> put finger to keyboard and composed:
I'm wondering if running a 3-volt device (cheap digital camera) on 3.3
volts will hurt it. Yeah, I coulda gotten a 3-volt wall wart to run it,
but it was expen$ive. The 3.3V regulator I got was a little more than a
buck. Haven't tried it yet.
Unless the 3.3V regulator is a fixed type, it may be possible to bring
it down to 3.0V by changing a feedback resistor. Can we see a photo of
the PCB?
It's just a TO-220 regulator, for chrissakes. An NTE something something
.... don't have it here at the moment, but it's just a fixed 3.3V
regulator. So no, not possible to rejigger it w/a resistor.
I'm just going to use it as-is. I don't think 10% overvoltage will hurt
the cam.
--
You were wrong, and I'm man enough to admit it.
- a Usenet "apology"
William Sommerwerck
Guest
Thu Mar 11, 2010 2:10 pm
Quote:
Unless the 3.3V regulator is a fixed type, it may be possible
to bring it down to 3.0V by changing a feedback resistor.
One assumes that a 3.3V regulator is a fixed regulator (or otherwise the OP
would not be having a problem).
Fixed regulators' outputs can be changed, too, but only raised. This is
usually done by inserting a Zener diode in the ground-reference line.
(CMIIW.)
Franc Zabkar
Guest
Sun Mar 14, 2010 10:20 pm
On Wed, 10 Mar 2010 21:38:23 -0800, David Nebenzahl
<nobody_at_but.us.chickens> put finger to keyboard and composed:
Quote:
On 3/10/2010 7:45 PM Franc Zabkar spake thus:
On Mon, 08 Mar 2010 15:20:07 -0800, David Nebenzahl
nobody_at_but.us.chickens> put finger to keyboard and composed:
I'm wondering if running a 3-volt device (cheap digital camera) on 3.3
volts will hurt it. Yeah, I coulda gotten a 3-volt wall wart to run it,
but it was expen$ive. The 3.3V regulator I got was a little more than a
buck. Haven't tried it yet.
Unless the 3.3V regulator is a fixed type, it may be possible to bring
it down to 3.0V by changing a feedback resistor. Can we see a photo of
the PCB?
It's just a TO-220 regulator, for chrissakes. An NTE something something
... don't have it here at the moment, but it's just a fixed 3.3V
regulator. So no, not possible to rejigger it w/a resistor.
I'm just going to use it as-is. I don't think 10% overvoltage will hurt
the cam.
I thought that a standard 3-terminal regulator with a 1A current limit
may not be appropriate for the task. That's why I assumed you had
something more sophisticated. After all, you did get the camera for
$1. :-)
- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.
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