Electric Adapter(power supply)

Thread Starter

dosyl

Joined Sep 27, 2013
9
Hi guys,
I'm new on this forum. I do electronic project not enough often.I believe what I want to ask is easy, but for me!!!!!!!!!
I have a Brother Ptouch 1290 that use 6 batteries AAA = 9volts. Brother sell an electric adapter for close of $25.00. I'm sure that I can made it myself (but with your help).
PTouch Electric Adapter3.jpg

When I put a 9 volts adapter in the socket I have .87 volts at the load of Ptouch(capacitor 3300 uF. Where the voltage are gone.

On the plan I write a Zener Diode but not sure if it is.

The adapter 9 volts without load have close of 13.5 volts. It's written 9 volts on. When I put a 9 volts adapter nothing happen.
 

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wayneh

Joined Sep 9, 2010
17,498
Your diagram doesn't make much sense - I think the bypass around the fuse is not right?

But anyway, I think your problem is that the load far exceeds the capacity of that adapter. Do you have any details about what your device needs and/or the rating of the adapter?
 

Thread Starter

dosyl

Joined Sep 27, 2013
9
Just buy a regulated 9V adapter.. Should be under $10..

Those who can't make..buy
I said that we can't put an regular adapter. Brother made his Ptouch for we buy their.
I want help to build it not for comment to buy one.
 

wayneh

Joined Sep 9, 2010
17,498
You don't need to buy the name brand, just any properly rated 9V adapter. In your case you need a rating of 1.6A or more. It'll cost you more to make your own unless you already have the transformer.
 

Thread Starter

dosyl

Joined Sep 27, 2013
9
You don't need to buy the name brand, just any properly rated 9V adapter. In your case you need a rating of 1.6A or more. It'll cost you more to make your own unless you already have the transformer.
Yes I have all to make it, and i have the time too. Need help only.:(
 

wayneh

Joined Sep 9, 2010
17,498
Yes I have all to make it...
What sort of transformer do you have - what is its output (voltage, AC or DC, and amperage rating)?

The standard DC wall wart configuration is AC transformer-bridge rectifier-filter capacitor. This produces unregulated, rippling DC.

For your application, I believe a voltage regulator (7809 for example) would also be a good idea. It would be nice to know if the name-brand adapter provides a regulated voltage. If so, I would say you need the regulation for sure. But it is possible the device handles voltage regulation internally. There's just no way to know without more information. Can you look at the manufacturer's adapter to get these details? Perhaps a link to it?
 

bertus

Joined Apr 5, 2008
22,278
Hello,

Here is a simple powersupply made by Bill_Marsden:



Make the 100 μF much larger, somewhere between 1500 and 3300 μF.
And take an 78S09 or an 78T09 in place of the 7812.

Bertus
 

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