Step 1: Parts list

L78M05CV  5V 500 Ma voltage regulator
9 volt battery snap
USB connector (female) ,or phone charger plug
of course soldering iron and some solder.
optional - extra wire ,heat shrink ,recharge able 9v battery ,multimeter (for checking if all are working correctly.)
I bought 9v 250 Mah battery for 6$. I think if you build this you'll need recharge able battery. For wire i just use wire from 9v battery snap.

Step 2: SOOO easy!

Picture of SOOO easy!
this step will show you how to connect parts correctly.
on usb that 2 middle pins you can just snap off.
voltage regulator's numbers side up.
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OwenH2 made it!2 months ago

Is this safe for your phone? Like day to day use? Or is it just for an emergency?

majenko3 months ago

I'm sorry, but that really is the worst possible design for a phone charger imaginable.

1. Where are the capacitors for the voltage regulator?

2. Why are there no D+ and D- resistors to enable charge mode?

3. How do you expect to charge a (typically 1500mAh) phone battery from a 500mAh 9V battery? (150mAh if you use a rechargeable one...!).

With modification it might allow you to use a brand new Alkaline battery to charge the phone enough to make an emergency call, as long as you don't want to say much.

this charger works for 5 secs after that it do not charge my phone but after disconnecting it and connecting it again with my phone it works for 5 secs again

PatrickS26 months ago

Would you be able to use this with a 9v power adapter? I need USB power from my pedal board. I have extra 9v cables, and I need to power a usb device on the board without running any extra power supplies. Could I use this adapter from the 9v power supply?

tim.leitzke.96 months ago

can I use such things like this (5v regulator) for the newer apple lightning connectors?mor do I need a different regulator?

SurajP6 months ago

using this circuit output raises from 5v to 6.6v after 30 min (input voltage 7.5v from adapter)

kushalverma3 years ago
if we supply 12v instead of 9v then will it work????
can we charge more than 2-3 mobile phones at a one time???????
plz rply
lorddavis6 (author)  kushalverma3 years ago
12v will work fine. If you add more usb conectors (red with red and black with black wire) on output conections , then you could charge multiple devices at the same time.

Be careful supplying much more than the intended voltage coming out of the voltage regulator. Cheaper 5v regulators have a drop-off voltage of about 2v, meaning you need to power it with at least 7v for it to deliver a proper 5v, but using more input voltage will result in significantly more heat coming from your regulator in which you really need a heatsink or you will most certainly melt the back of that plastic casing for your batteries!!! I have burnt myself more than once this way :)

kmagic44 years ago
sorry but your circuit is wrong.... the way you have it drawn the gnd on the regulator is going to the posotive side of the battery and that doesnt make any sense...gnd should go to your usb and negative side of battery....the output should go to the other side of your usb and you in should go to the posotive side of your 9v.. and the switch can be thrown in anywhere.... correct me if im wrong but i usually am not..LOL!
lorddavis6 (author)  kmagic44 years ago
i"ve connected this charger exactly like it is showed schematic and in real life model too. it is working very well,but regulator may get hot! :( regulator is that side up what is showed in picture at (step 1).sorry if you can,t understand some words,i"m not from USA or UK.
dmegill lorddavis611 months ago
Just take a washer and bolt it to the regulator for a plain and simple heat sink. Preferably aluminum. But other than that you may be able to find small heat sinks in old computers
lorddavis6 (author)  kmagic44 years ago
and thanx for correcting even ,if you are wrong ,but it is nice if someone helps!

Now can you use this to charge the 9v batty also? and if you did what would keep the battery from over charging and exploding? Does any one know how to make a 9v battery charging circuit?

please help me i did a project like this but with a added led and i hooked up everything right and everything works but when i plug my phine into the usb the led goes off and my phone doesnt charge
Vanila4 years ago
Will this word with the new Ipod Touch 4?
Data643 Vanila4 years ago
No, iPods & iPhones need a special circuit. I've tried this schematic and it did not work with my iPod Touch

You will need to make the circuit from here:

It uses a few resistors to give voltage to the two middle pins

Xixfas Data6431 year ago
yes someone finally gets it!
Thanks for the link! I'm going to go to the local electronics shop to buy the components now.
lorddavis6 (author)  Data6434 years ago
thank you ! I Don,t own any apple product
Themaxim2 years ago
How many volt does a ipad 2 need for to charge?
you need a resistor on the info wires for ios devices Themaxim2 years ago
5v and about 1000mah +
lorddavis6 (author)  Themaxim2 years ago
It should be written on the charger that it came with or you could always search it on Google.
sraul11 year ago
Middle two wires are for Data + & Data - ...
ignore them .. just use two extreme ends wires ... those carries ~5V current ! ...
Xixfas sraul11 year ago
you need a resistor on the info wires for ios devices
i made this ..but my phone is charging with discharging means if puted for one hour its only charge 10% after that the percentage is not increased but my phone is shows it is charging ..after that if restarted my phone it becomes 0 % nothing charged what can i do please help me:(
Cristu1 year ago

Very nice instructable, doable in less than 15 minutes even for a beginner in soldering like me. I've made it, only that I didn't use the switch and everything is more compact because I'd like to put it in resin or something to make it more solid so I could use it without worrying that the wires will snap off. Also instead of the female usb port I've used a male micro usb to plug it directly in my phone.

Keep it up!
NoVet541 year ago
My female usb port comes black, red, green, and white wires. What should I do?
Ibenos1 year ago
How many volts is the voltige regulator???
ebaratita3 years ago
i think you need 3 capasitors for this one
lorddavis6 (author)  ebaratita2 years ago
This is very basic charger.I tried to make it from as less parts as I could. Maybe you should make your own version of this ckarger
Hello,im just wondering if you know of any electronics that i can get a female usb connctor sorry im cheap and dont want to have to buy one
lorddavis6 (author)  fancysaukrel2 years ago
You could get a female usb connector from a cheap usb extender cord
lorddavis6 (author)  fancysaukrel3 years ago
You can get USB (normal kind) extender and cut it of.
You can buy USB female connector separetly from makershed or godaddy ,or some websites like that.
BTW Sorry for my bad english skills. :)
lorddavis6 (author) 4 years ago
sorry for so little image in 2nd step.
It is correct, the gnd comes form the batterys negative and goes to regulators centre, where its supposed to go, then it goes to the usbs negative :) everything is correct
seben3 years ago
will this work for charging my psp 3001, and do i need a female usb from a old computer or does it half to be from a wire.
dfalk3 years ago
Hi nice!

Can u link where I can buy L78M05CV 5V 500 Ma voltage regulator
lorddavis6 (author)  dfalk3 years ago
You can find it at radioshack or bought mine at local radio electronics store.
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