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Making an adopter...

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lord loh.

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I made an adopter to deliver variable voltages using an LM 317 IC. The voltage is observabale on the multimeter. But When I try to charge a Nokia phone, a message called 'not charging' is displayed. What could be wrong ?

I tried changing the polarities as well....
 
I just found out that the wire I was using to connect to the phone had a resistance of 2k2Ω.... So the voltage drop across the wire was so large that the phone did not get the required voltage. The original nokia charger was rated 800mA and 5.7v. I shall try changing the wire.

The LM317 IC can deliver 1.5A my transformer is rated 1A. No I measured the voltage without any load. The voltahge is not supposed to change till the 1.5 A limit of the IC is reached. Then of course the voltage shall begin to fall...loading.
 
what? 2 kOhm! :shock:

there is somting wrong since even an 20m wire wodnt be close that resistance.

mesure the voltage whith an light bulb or an 50Ohm resistor conected to the output.
 
I know it is crazy!!! but the measurement with VOM at all range settings gave me the same results. And so the observation explain. But how... I cannot think of.

But what is the use of measuring with 50 ohms at output ?

And do you mean the output of the ckty or at the end of the 2k2 ohm wire ?
 
lord loh. said:
I know it is crazy!!! but the measurement with VOM at all range settings gave me the same results. And so the observation explain. But how... I cannot think of.

There are two possibilities!.

1) The wire is faulty!.

2) The wire is designed to have that resistance, it's the current limiter for charging the batteries.
 
put an 50Ohm resistor directly on your regulators output to simulate a load and meshure the voltage whith your multimeter over the resistor.

use an 1/2 to 1W resistor since doing this will thurn it in to a heater (500mW of power)

use an nother wire that is more "normal" since a wire like that will olny let trugh 2,5mA at 5V
 
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