AC adapter voltage for digital camera
Dan Mitchell
As is typical of digital cameras, it goes through batteries like there's no
tomorrow. Fuji sells an AC adapter for the camera which can be used both to
power the camera when dl'ing pics to the PC, as well as to use when taking
photos near an AC line (which I would do a lot since I want to use it to
photograph items for auction on Ebay). I would like to build an adapter,
both because I like to, and because the Fuji adapter is $40 (which seems
nuts)! This is very straightforward of course, I have built many regulated
supplies for projects. The trouble is setting the correct voltage. Camera
runs on 4 AA batts, or 6 volts. BUT, the Fuji adapter is spec'd at 5 volts,
and the jack on the camera is also marked 5 volts. BUT, when I have run the
camera on 5 volts (both from a supply I made for it using a 7805 regulator
and at a measured 5V from my variable voltage bench supply) the camera will
not TAKE PHOTOS properly. It will dl to the pc, but when the extra current
of taking images is attempted at 5 volts, the rear lcd screen drops out &
the pics are not stored to the disc. Wondering about the voltage, I bumped
my bench supply up to 5.5V, and the camera seems to function fine on this
voltage. I am wondering if I could just go ahead & feed it 6 volts since I
have a nice 6 volt 1200 ma wall plug supply which I could easily use just by
changing the jack. I'm leery of trying this though since the camera was
$400 & I don't want to fry anything. My 2nd option is to build a supply
around an LM317 variable regulator & just set it to 5.5V. Am I correct to
assume the camera circuitry actually runs on 6 volts, given the 4 AA batts?
Could it be the camera internally adjusts the 6 volts from the batts to ~5.5
before delivering them to the circuitry??? Seems unlikely, but I guess
possible. I guess the best thing would be to measure one of the $40 Fuji
supplies under actual camera load & see what it's putting out, but needless
to say this isn't an option.
TIA,
Dan
Bill Jr
and it will bump it up to about 5.6 volts.
Good Luck,
Bill Jr
"Dan Mitchell" <progr...@hotmail.com> wrote in message
news:b3hek9$1mo1it$1...@ID-166021.news.dfncis.de...
Sofie
To jog your thoughts a little here:
4 AA batteries don't necessarily produce 6 volts...... 4 Alkaline batteries
under a light load may come close to 6 volts @ 1.5 volts each ..... but,
more than likely you are using Nice or Nigh batteries that usually produce
about 1.25 volts per cell........ so 4 batteries under load might produce
not much more than 5 volts.
Did you measure the current that the camera uses when in the shooting mode?
... if it is anywhere near 1 amp it could be that your home-made power
supply with the 7805 is either current limiting or the input voltage to the
regulator chip is too low under load and you may need a stiffer transformer
or one with a higher voltage secondary winding.... or a bigger main filter
capacitor....... or a beefier power supply altogether....
....or just bite the bullet and purchase the $39.95 AC Adapter from Fuji....
it just might be cheaper and easier..... and safer for your new expensive
camera.
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
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.
"Dan Mitchell" <progr...@hotmail.com> wrote in message
news:b3hek9$1mo1it$1...@ID-166021.news.dfncis.de...
Sofie
"Sofie" <so...@olypen.com> wrote in message
news:v5oq0b4...@corp.supernews.com...
> Dan Mitchell:
> To jog your thoughts a little here:
> 4 AA batteries don't necessarily produce 6 volts...... 4 Alkaline
batteries
> under a light load may come close to 6 volts @ 1.5 volts each ..... but,
> more than likely you are using Nice or Nigh batteries that usually produce
My spell checker was too aggressive and I didn't catch the error..... "more
than likely you are using NiCad or NiMh batteries..........."
Dan Mitchell
batteries. I plan to get 1800mAh NiMH's & a charger for it later. Yes, I
did measure the current being consumed, under maximum load it's just shy of
800ma. Interestingly, this approximately coincides at 6 volts with the
camera's rated power consumption of 5 watts. I don't think a lack of power
is the issue; the supply I designed uses a 24 volt center tapped xformer, is
well filtered and is large enough and puts out a constant 5.12 volts under
all camera load conditions. The 7805 in question is a TO220 variety, which
with the provided heat sinking is good for 1.5 amps. In any case my bench
supply puts out around 3 amps.
Yeah, buying the ridiculously overpriced OEM supply would probably be
easier, but I'd prefer to build my own, and just can't bring myself to be
gouged by paying $40 for a simple wall block supply that should be around
$10.
Dan
"Sofie" <so...@olypen.com> wrote in message
news:v5oq0b4...@corp.supernews.com...
Dan Mitchell
what the Dr. ordered, I'll give it a try!
Dan
"Bill Jr" <bi...@nospam.usa2net.net> wrote in message
news:nfX6a.36148$163.1...@twister.tampabay.rr.com...
Jim Yanik
> Thanks for the reply. At the moment the camera is running on alkaline
> batteries. I plan to get 1800mAh NiMH's & a charger for it later.
> Yes, I did measure the current being consumed, under maximum load it's
> just shy of 800ma. Interestingly, this approximately coincides at 6
> volts with the camera's rated power consumption of 5 watts. I don't
> think a lack of power is the issue; the supply I designed uses a 24
> volt center tapped xformer, is well filtered and is large enough and
> puts out a constant 5.12 volts under all camera load conditions. The
> 7805 in question is a TO220 variety, which with the provided heat
> sinking is good for 1.5 amps. In any case my bench supply puts out
> around 3 amps.
>
> Yeah, buying the ridiculously overpriced OEM supply would probably be
> easier, but I'd prefer to build my own, and just can't bring myself to
> be gouged by paying $40 for a simple wall block supply that should be
> around $10.
>
> Dan
The camera probably has a regulator IC inside of it that regulates to 5v
for the digital logic.It thus would need some overhead to regulate
properly,even a low-dropout regulator.
Have you measured the actual output of the Fuji wall-wart? It might not
even be a regulated supply.
--
Jim Yanik,NRA member
remove X to contact me
Dan Mitchell
one. From pics I've seen of it though, I suspect it isn't regulated (just
looks like your typical smallish black plastic cube). I'm making mine
regulated just to be on the safe side. Plus I have all the bits, so why
not?
Dan
"Jim Yanik" <jya...@kua.net> wrote in message
news:Xns932E6FE4B89...@204.117.192.21...
Dave D
"Dan Mitchell" <progr...@hotmail.com> wrote in message
news:b3itmk$1lqpuk$1...@ID-166021.news.dfncis.de...
> Jim, no I haven't, that would be the ideal test, but I don't have access
to
> one. From pics I've seen of it though, I suspect it isn't regulated (just
> looks like your typical smallish black plastic cube). I'm making mine
> regulated just to be on the safe side. Plus I have all the bits, so why
> not?
>
> Dan
It could well be a miniature switch mode PSU, they are very common these
days and even some cheap devices like scanners use them. One thing I'm
fairly sure of, if the camera socket says 5V, then 5V is what you should
feed it. You risk ruining a perfectly good camera by experimenting with
higher voltages. My guess is the current demand from the camera will be very
high at certain times, much higher than a 7805 can supply. Personally, given
the value of the camera, I'd just buy the correct PSU. Think about what will
happen if your homebrew PSU fails and puts unregulated voltage into your
camera, you won't get a second chance.
Dave
Sofie
I absolutely agree with Dave D..... it is an expensive camera.... bite the
bullet and purchase the correct "factory" AC Adapter.
Certainly you can finally figure this out and "make" your own, but you will
probably pay just as much or more when it is all done.... and even though I
am certain that you will do a nice job..... it won't look right, it won't
"fit" right, and it won't work like the original factory unit.......
I have been there and done that myself many times....... given the troubles
you are experiencing and the value of the camera...... skip going out to
dinner some evening and use the money you saved to buy the correct power
unit.
--
Best Regards,
Dan Sofie
Electronics Supply & Repair
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"Dave D" <som...@somewhere.com> wrote in message
news:b3ll9d$ntb$1...@helle.btinternet.com...
Bruw
Allow for at least 1 A current flow.
Dan Mitchell
volts (using Bill jr's idea of a forward biased diode in the ground leg of
the 7805 to boost the output slightly). The TO220 7805 is rated at 1.5
amps, I used a huge heatsink which even after 40 rapid fire flash shots
barely gets warm. I know the camera body says 5 volts, but it just would
not run on this, again even from my bench supply which easily puts out 3
amps. That's the confusion which had me posting here to begin with.
Anyway, I modified an old modem power supply with a 20VAC 2 amp center
tapped output which I picked up free a number of years ago (I've got tons of
this stuff ;-). Since everything I used I had on hand (except the 4.00mm x
1.7mm plug), it ended up costing about $1.29. Even looks pretty good, if I
do say so myself, check it out at http://krntyusp.50megs.com/photo.html
(asuming this freeby link which I just set up quickly actually works ;-)
Thanks again everyone, great group!
Dan
Franc Zabkar
finger to keyboard and composed:
>Must be regulated 5V DC. Anything higher can fry the camera electronics.
You mean like four fresh 1.5V alkaline AA's?
-- Franc Zabkar
Please remove one 's' from my address when replying by email.
Dave D
"Franc Zabkar" <fza...@optussnet.com.au> wrote in message
news:3e5fbf38...@news.optusnet.com.au...
> On Fri, 28 Feb 2003 11:33:04 +1000, "Bruw" <wit...@bigpond.com> put
> finger to keyboard and composed:
>
> >Must be regulated 5V DC. Anything higher can fry the camera electronics.
>
> You mean like four fresh 1.5V alkaline AA's?
>
Just because the battery compartment is rated at 6V doesn't mean the power
jack is. If the wall adaptor turns out to be a 5V regulated supply,
bypassing the cameras internal regulator, then supplying 6V into the socket
could be a problem. The point is, we don't know how this thing operates, and
conjecture can end up being expensive.
Dave
Dan Mitchell
source amply (you'll pardon the pun) able to meet the current requirements,
and the camera was not getting sufficient power (lcd display dropped out
when a picture was taken, image failed to record to disc, etc). It is only
when I increased the supplied voltage to 5.6/5.7 volts that the camera
operated properly off-battery. Frankly, I would not be at all surprised if
Fuji knew full well 5 volts was insufficient, and that non-OEM supplies
rated at 5 volts would not operate the camera, so users would be forced to
opt for the ridiculously priced Fuji supply.
Anyway, the camera works fine on the supply which I enjoyed making, & I am
happy with it and the $$$ savings.
Dan
"Dave D" <som...@somewhere.com> wrote in message
news:b3ogm3$cvd$1...@helle.btinternet.com...
Bill Jr
Bill Jr
"Dan Mitchell" <progr...@hotmail.com> wrote in message
news:b3o5se$1ok6hj$1...@ID-166021.news.dfncis.de...
Jim Yanik
You might want to add an overvoltage crowbar circuit,and a fuse to protect
against regulator failure. SCR,a zener and a resistor,with a fuse for it to
blow if the output rises over maybe 5.8 volts.
Asimov
--- on the topic of "Re: AC adapter voltage for digital camera"
I'll go one better: the 5 volt label marking was a misprint and it
should have read 6 volts instead.
A different case I know of is for instance switching supplies will
actually operate cooler at a slightly higher input voltage because the
switching angle then becomes shorter and also draw less current. I have
a USR Sportster 33.6 external modem which is labelled 9 volts AC but
been using it with a 12 volt pack for about 5 years, and it's very cool.
DM> From: "Dan Mitchell" <progr...@hotmail.com>
DM> Yes, but again, *I APPLIED 5 REGULATED VOLTS TO THE SUPPLY JACK* from
DM> a source amply (you'll pardon the pun) able to meet the current
DM> requirements, and the camera was not getting sufficient power (lcd
DM> display dropped out when a picture was taken, image failed to record to
DM> disc, etc). It is only when I increased the supplied voltage to
DM> 5.6/5.7 volts that the camera operated properly off-battery. Frankly,
DM> I would not be at all surprised if Fuji knew full well 5 volts was
DM> insufficient, and that non-OEM supplies rated at 5 volts would not
DM> operate the camera, so users would be forced to opt for the
DM> ridiculously priced Fuji supply.
DM> Anyway, the camera works fine on the supply which I enjoyed making, &
DM> I am happy with it and the $$$ savings.
DM> Dan
... Now touch these wires to your tongue!
Mike
D" <som...@somewhere.com> which said:
The HP912/Pentax EI2000 is even more peculiar .. internally it uses 4 AA's
but the external input requires 9V regulated at 1.2A. The commercial unit
is a switched mode PSU and it really does provide 9V ... but why? To have
a design that has to seemingly "lose" 3.6W is a mystery. By the way my
example of the camera will not work with lower than 8.5V!
Mike
Please remove DE SPAM to e-mail
Dave D
"Dan Mitchell" <progr...@hotmail.com> wrote in message
news:b3on7i$1p2euq$1...@ID-166021.news.dfncis.de...
> Yes, but again, *I APPLIED 5 REGULATED VOLTS TO THE SUPPLY JACK* from a
> source amply (you'll pardon the pun) able to meet the current
requirements,
I realise that, but having a PSU rated at 3Amps and being able to supply
large transient current demands isn't necessarily the same thing, for
instance it could have an inadequate reservoir cap, which would make it
drop significantly for a millisecond. You'd need to monitor the voltage
closely to see if it is up to scratch under load.
> and the camera was not getting sufficient power (lcd display dropped out
> when a picture was taken, image failed to record to disc, etc).
Which implies the current draw caused a voltage drop. The proper supply
probably uses feedback, ie samples the output voltage and corrects it. A
standard PSU likely won't cut it hence your problem. If you must make your
own PSU I would build it around an op-amp with voltage feedback, it's very
very easy to do and there's plenty of schematics on the web. This will offer
much better regulation than the 7805.
>It is only
> when I increased the supplied voltage to 5.6/5.7 volts that the camera
> operated properly off-battery. Frankly, I would not be at all surprised
if
> Fuji knew full well 5 volts was insufficient, and that non-OEM supplies
> rated at 5 volts would not operate the camera, so users would be forced to
> opt for the ridiculously priced Fuji supply.
>
I very much doubt it. They don't have to print a voltage on the case at all,
especially as they supply the correct PSU.
> Anyway, the camera works fine on the supply which I enjoyed making, & I am
> happy with it and the $$$ savings.
>
> Dan
>
As long as you are happy. All I was trying to do was draw your attention to
the risks involved.
I would follow Jim Yanik's advice and build a crowbar circuit, it could save
you a few hundred dollars!
Dave
Franc Zabkar
<som...@somewhere.com> put finger to keyboard and composed:
The camera is designed to run from 4 rechargeable batteries, ie
unregulated 4.8V - 5V. It can also operate on 6V alkalines. If the
circuitry were meant to operate at a regulated 5.0V, then, AFAIK, it
would need an unusual DC-DC converter, ie one that could step up as
well as step down.
Furthermore, if it is a modern camera, I would expect that its logic
would operate at 3V rather than 5V. I know that the original
CompactFlash memory sticks, for example, can run at either 5V or 3V,
but from a power saving perspective it makes more sense to design for
3V. I'm not sure, but perhaps the new memory cards (eg SD, Smartmedia)
are exclusively 3.3V devices.
As for why Fuji specify a regulated 5V adaptor, it could be that it is
cheaper to produce a high current (1-2A), regulated, SMPS adaptor than
it is to manufacture its heavy, unregulated, low current, iron
counterpart.