Canon A 40 to 80 AC adapter question - polarity.

"Eatmorepies" writes:

I will try to glue them back on but I'm not hopeful.

Yeah, they're probably under a lot of stress, and the original part is
probably fibre-reinforced plastic.

But Canon want 50 ukp for the adapter. It's only 4.3V DC and I can easily
make a stabilised 4.3V supply with an LM317 - if I know which part of the
plug of the real Canon adapter is the positive connection.

So, if you have a Canon AC adapter for your A 40 to 80 camera, can you tell
me if the outer electrode of the plug is positive or negative?

I believe it's centre positive, outside negative; but I don't have the
camera or adapter here. Send me email and I'll check at home.

By the way, I've tried 5 V and it works fine, so you can use a plain 5 V
regulator. But you need more than 1 A output, so a plain LM317T might
not be up to the job. The camera manual tells you what current the
Canon adapter is rated for; your adapter should provide at least that
without going into current limit.

Dave

"Dave Martindale" wrote in message ...
"Eatmorepies" writes:

I will try to glue them back on but I'm not hopeful.

Yeah, they're probably under a lot of stress, and the original part is
probably fibre-reinforced plastic.

But Canon want 50 ukp for the adapter. It's only 4.3V DC and I can easily
make a stabilised 4.3V supply with an LM317 - if I know which part of the
plug of the real Canon adapter is the positive connection.

So, if you have a Canon AC adapter for your A 40 to 80 camera, can you tell
me if the outer electrode of the plug is positive or negative?

I believe it's centre positive, outside negative;

That's correct.

but I don't have the
camera or adapter here. Send me email and I'll check at home.

By the way, I've tried 5 V and it works fine, so you can use a plain 5 V
regulator. But you need more than 1 A output,

Also correct. Preferably 1.5A, 1.2A at a minimum.

Rick

so a plain LM317T might
not be up to the job. The camera manual tells you what current the
Canon adapter is rated for; your adapter should provide at least that
without going into current limit.

Dave

So, if you have a Canon AC adapter for your A 40 to 80 camera, can you
tell
me if the outer electrode of the plug is positive or negative?

I believe it's centre positive, outside negative;

That's correct.

but I don't have the
camera or adapter here. Send me email and I'll check at home.

By the way, I've tried 5 V and it works fine, so you can use a plain 5 V
regulator. But you need more than 1 A output,

Also correct. Preferably 1.5A, 1.2A at a minimum.

Rick


Rick - you may know this one. If there are rechargeable cells in the camera,
will the connection of the AC adapter charge them?

John

"Eatmorepies" wrote in message ...


So, if you have a Canon AC adapter for your A 40 to 80 camera, can you
tell
me if the outer electrode of the plug is positive or negative?

I believe it's centre positive, outside negative;

That's correct.

but I don't have the
camera or adapter here. Send me email and I'll check at home.

By the way, I've tried 5 V and it works fine, so you can use a plain 5 V
regulator. But you need more than 1 A output,

Also correct. Preferably 1.5A, 1.2A at a minimum.


Rick - you may know this one. If there are rechargeable cells in the camera,
will the connection of the AC adapter charge them?

No, at least not on the A-series.

Rick

On Tue, 19 Oct 2004 20:18:18 +0100, "Eatmorepies"
wrote:

Hello

I dropped the A80 and broke the 3 little catches off the battery
compartment.

I will try to glue them back on but I'm not hopeful.

However, the camera is usually used in just the one lab. at work. I thought
to buy an AC adapter and simply glue the battery door shut and run the
camera off the mains.

But Canon want 50 ukp for the adapter. It's only 4.3V DC and I can easily
make a stabilised 4.3V supply with an LM317 - if I know which part of the
plug of the real Canon adapter is the positive connection.

So, if you have a Canon AC adapter for your A 40 to 80 camera, can you tell
me if the outer electrode of the plug is positive or negative?

Thanks

John


John,
since you mentioned an "LM317" (adjustable voltage regulator),
consider some advice from a retired electronic technician. Follow the
K.I.S.S. principle & consider this option: Don't reinvent the wheel,
buy a regulated 5VDC "wall wart" (plug-in wall transformer) mail order
surplus if possible & place a general purpose silicone diode in series
with 1 lead which will drop the output by about 0.6VDC thus lowering
it to about 4.4VDC which should be close enough. 5VDC, 1.5A+
regulated wall warts or power supplies are very common & can often be
had cheaply.

Optionally, you may wish to add an in-line 3A fuse. Just make
sure the wall wart is rated for 1.5A or more & select a diode that can
handle both the 1.5A & the dissipate the heat, a 3A or higher diode
should do fine. It took me years of doing things the hard way, to
learn how to adapt things for my needs rather than to engineer & build
what I needed from scratch.

No regrets, because doing so has also expanded my knowledge
but as 1 gets a bit older & hopefully wiser, 1 tends to learn to do
things in more time efficient ways. Thus it is for this reason that I
offer you this suggestion for your consideration with the hope that
you find it of value. Lastly as others have noted center is + &
outside is - on the connector.

Respectfully, DHB


"To announce that there must be no criticism of the President,
or that we are to stand by the President, right or wrong,
is not only unpatriotic and servile, but is morally treasonable
to the American public."----Theodore Roosevelt, May 7, 1918