3,7v emergency charger Nokia cellular with 9v battery

Hello to all. I wanted to propose to you a simple cellular charger with technology of low level that however works and carries out its task perfectly. Draft of a cellular charge of emergency that can be indispensable if it is found to us with the batteries is down and without a station of charge to hand capacity that is in all those unforeseeable situations that before or after can happen.

Step 1 The components

The circuit is much simple one and comprises besides the battery of 9v a made reducer of tension of approximately 2v from 4 diode valves 1n4007, in series to a resistance PTC, member that I have extracted directly from a local p0wer source of cellular from 3,7v that it must have a function to stabilize the tension and to make to limit the current in case too much absorption.

Comments

[tkjtkj]

Thanks, but we would welcome a schematic drawing with all items labeled .. eg i dont know what a PTC is either .. the picture SEEMS to be a very small capacitor . 

[davelectronic]

Positive temperature co efficient

[tkjtkj]

"Positive Temperature Coefficient (PTC) thermistors are thermally sensitive semiconductor resistors which exhibit an increase in resistance at a specified temperature. Change in the resistance of a PTC thermistor can be brought about either by a change in the ambient temperature or internally by self heating resulting from current flowing through the device"

http://www.educypedia.be/electronics/resistorsnon.htm

 

[arifuddin2007]

 What is the value of the capacitor used?   Is it a 22nF capacitor?

[torx]

It is not a capacitor but it is a resistor ptc.
I don't know much about it. I found at the Interior of the PSU 3 .7V and its value for ohm is approximately 1 ohm.
Thank you for the question , you are interested in the realization of the project?

[dadawawa]

... is that fuse exactly 100ma?...where can i buy this fuse?.. thanks

[V-Man737]

Sorry if I sound daft, but... Why are four diodes used? Would one be enough? Also, does the absorption limiter need to be connected directly to the feeding thorn? Or does it go between the cable and a diode? We are good to be spitting pretty colors! V-Man737

[torx]

The diodes 1n4007 are in series in order to obtain a voltage drop of approximately 2v, in order arriving to approximately 7v that it is the tension not stabilized that I have found on the heads of the local power source 3,7v of the nokia. Resistor PTC was in series to the feeding to the inside of the same local power source. In other words I have recreated the conditions (approximately) that there are with the local p0wer source originates them. In phase experiments had tried they to diminish the tension in order to approach to me the declared ones 3,7v but telephones sends I the written one to me of the type " not possible charger"

[V-Man737]

That is good to know! I was not knowing diodes had voltage drop.

[claywuu]

incrivellll

[torx]

Thanks for the observation to Bersek87 !

[Berserk87]

the 1A fuse you put in there is not needed. a 9V battery isnt going to output anything close to 1A.

[torx]

Just friendly observation my! In effects I did not know the current short-circuit of this battery and have put a fuse seemed that me of just value. I supply quickly to the measurement of the instantaneous current of s.d in order connecting the optimal fuse!

[FERNANDO19BLO]

(removed by author or community request)

[Berserk87]

lol.

[torx]

Not are an capacitor but an PTC ; I pray you to moderate the terms !!

[FERNANDO19BLO]

Ah ok, sorry.