Thinking about it, the 0.7V diff might be the drop across a rectifier diode, so maybe all the camera needs is 3VDC.
You might try using a 3A rectifier diode to drop the 4.5V down to 3.8 or so volts.
See:
-- To reply no_ HPMarketing Corp.
the 3 volt level should be ok since its most likely is putting out more than 3 volts to start with.
David Turrell wrote:
I'm guessing the reason the voltage is higher than the battery voltage is that there's a protective diode or something. But 3 volts may well work.
2500 mA is a *lot* of current!!!! Does this camera really draw 2500 mA? If so, it must run down its batteries almost instantaneously.Does this camera have a flash built in? If so, I'll bet the heavy current drain is only for charging the flash, and that without flash, you could get by with a considerably lower-current power supply.
I recently purchased an HP Photosmart 435 digital camera. I'm looking for an A/C adapter that is less expensive than that made by HP, which costs ~$50 (the camera itself was only ~$100, and I'm not necessarily going to get another HP camera).
The power requirements for the camera, via A/C adapter, are listed as 3.3 to 3.7V and 2500mA. I haven't been able to find a generic adapter that matches those specs.
The closest that Radio Shack seems to have, of their standard, non-adjustable adapters, is 3V and 500mA. This adapter system has the advantage of a wide array of tips, the smallest of which (female,
0.7mm interior diameter) would seem to fit the HP camera.While 3V seems too low, I wonder how the camera is able to make do with two 1.5V batteries as a power supply!
A Radio Shack universal adapter, which I didn't see, would, based on the one I have for a radio, have 3, 4.5, 6, etc. volts, which seems not close enough; and it probably wouldn't give the correct amperage.
Digi-Key's catalog has a wider range of voltage and amperage choices, but only matching the voltage, not the amperage. Also, I don't see a standard tip for them that is small enough for the camera. A custom-made tip, which they offer, would possibly bring the cost to where I might as well buy HP's version.
There's always the possibility of a jury-rigged device, but I'm trying to avoid something that messy.
What substitutions are possible under the circumstances?
-- David Turrell Domain: panix.com
Hi...
Respectfully, no it sure won't...
The original puts out 2.5 amps; whereas the rs version delivers only half an amp. That's a world of difference.
Ken
Jamie wrote:
is
work.
mA?
And a few hundred uF at 330VDC is a lotta capacitor to charge up in a few seconds. And that takes a lotta current, maybe not forever, but for quite a few seconds.
No, they're 2000 mAh which means they should last for the better part of an hour. But a camera isn't on very long.
current
could get
The LCD and backlight demand a lot of current, too. A lot.
Another factor not yet mentioned is that the supply *may* be able to recharge the cells while supplying power for taking more photos.
-- Graham W http://www.gcw.org.uk/ PGM-FI page updated, Graphics Tutorial WIMBORNE http://www.wessex-astro-society.freeserve.co.uk/ Wessex Dorset UK Astro Society's Web pages, Info, Meeting Dates, Sites & Maps Change 'news' to 'sewn' in my Reply address to avoid my spam filter.
I've been fooling with my 435 power supply because the battery grain is so high on these. The NiMH cells only have 1.2V nominal and fully charged they run the camera fairly well, but within a couple days they are in the low battery mode. So I searched for a jack to use on the AC/3.3V input and found one at an electronics store for $1.99. It's the same size as slot car power supply jacks and Radio Shack sells them for $4.95. I am sure you can use a 3.6V cell phone charger on that jack with no harm. At least it worked for me. However, the charger will try to charge any batteries in the camera. I did not want that happening. What I was really after is to put a DC source into that jack so I could furnish more total power to the device. So that idea flunked my testing.
What I ended up doing was working from the battery compartment. I took an old AA cell and cut it in half. I cleaned out the inside. Then I ran a wire to the plus and minus ends. I replaced the missing half of each cell with a wood dowel with a hole drilled in the center. In essence I made these fake batteries to put into the battery compartment and run a cable out the door, with a slot cut in the door. I took a 3.6V cell phone battery (removed from the case) and cabled it to that compartment. Fully charged the battery puts out 4.2V. I estimate the dam thing will take 200 pictures on a charge, but I recharge at 3.7V. I took the chance of over powering the camera because I was fed up and got to the point that I considered it expendable. I was stupid lucky this time. I have the power supply problems absolutely solved. I've taken 600 pictures with no problem from a power standpoint. I often get dark pictures and always have, but that's an unrelated issue. The white balance and E/V adjustments don't fix that consistently.
That's what I did anyway.
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