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Need help with 6.5 V AC adapter

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I have a cordless phone base that requires 6.5 v, and i don't have the original ac adapter, so i made one from 9 v adapter, i unwind the transformer to 8v ac and turned it to dc with rectifier, bu when i add a capacitor, the voltage goes up to 10v DC.

should i use it like this with capacitor or without or should i unwind the transformer more until i get 6.5V with capacitor attached?
 
If the phone base expects 6.5VDC then that's what you should give it. 10VDC will almost certainly fry it. But you mention "the original AC adapter", so is the base expecting an AC input?
 
the original adapter is ac-dc

should i unwind the transformer more to 6.5 v dc output ( with rectifier and capacitor ) or should i just remove the capacitor, ( when i remove the capacitor its 6.5 v ) and leave the transformer as it is ?
 
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Was the original adapter a transformer (wall wart) or a switching power supply?

Look at the label near where the wall-wart plugs into the appliance. If it expects DC, the label will show polarity shown with a +-. If it expects AC, the label will show ~ ~.

If the original adapter was 6.5Vdc@xxxmA , the no-load DC output voltage is likely to have been about 9V (6.5*1.4)...
 
The original is 6,5v DC on voltmeter showing 7v dc i am sure.

the ac-dc adapter that i now want to use was 9V dc output( says on the sticker) but voltmeter shows 16v dc, inside it has a transformer that gives out 11v ac that i later unwind from 11v ac to 8v ac and then turned it to 6,5v dc with a rectifier so when i put the capacitor on the rectifier output on the voltmeter i get 10v.

please answer me this :
should i unwind the transformer more to get 6.5 v dc output ( with rectifier and capacitor ) ?

or should i just remove the capacitor, ( when i remove the capacitor from rectifier i get 6.5 v dc on the voltmeter) ?
 
Calculate as MikeMl said. Use capacitor and connect load (your cordless phone?) and measure or get 6.5V. Voltage at transformer output is load depended so.
 
i don't understand if i connect my phone to 10 v it can fry it.
so i should unwind the transformer until i get 6.5v dc with with rectifier and capacitor right?
 
The wall warts for my Panasonic phone system are labeled 5.5V 500mA and unloaded they output about 6.55 Volts. Wall warts are not the most accurate sources of power. I have four and they are all the same. There were originally 5 of them but a local lightening strike ate one. I replaced it with a 7 Volt 1 Amp (current doesn't matter as long as it is enough) and that has been working about a year with my hack job. While I don't know your location wall warts are cheap and abundant so I would just look for a close or correct match, making sure of connector polarity.

Ron
 
unregulated wall transformers are always rated V at rated current and no load is 40% higher due to average to peak conversion.

if voltage drop is high inside phone, the internal regulator may overheat as current drops and voltage rises increasing power dissipation across internal regulator if it is linear.

if SMPS then it may be tolerant to higher V but limited by the capacitor values , so if overvoltage you can blow the caps. So is it a SMPS or linear regulator inside?

You open up phone to make sure or just guess and take a risk.

If the original was not 40% higher no load then it did not have a capacitor inside so drop is just the winding loss. Retest your transformer with no load and load with no cap and report back.
 
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inside the phone there is only one board with micro components ( like a cell phone), i plunged in this 10v adapter it works but for how long i don't know so when i measure the voltage with phone attached it is 9v

i think i should unwind the transformer more until i get 5.5 v AC and when i turn it to DC with rectifier, and add a capacitor it should be around 6.5 - 7 v dc am i right?
 
probably, can you answer my question? is it a SMPS (coil near DC ) in or linear regulator inside? and what cap V
 
i think i should unwind the transformer more until i get 5.5 v AC and when i turn it to DC with rectifier, and add a capacitor it should be around 6.5 - 7 v dc am i right?
Do same as you saying and feel free!
 
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