Volts from an USB cable

I need to know how many volts a usb cable provides from a laptop. I couldnt find any information on google and I know that someone here has to know.

Posted by allstarn07 10 years ago


Power Supply

With this circuit, does it matter how many amps the input is rated at? The output is supposed to be 2 amps at 9 volts

Posted by TheLostAmish 9 years ago



5 volts ballast

Can I have the circuit for the 5 volts cfl lamp ballast. Please! Thanks.

Posted by remyjovero 4 years ago


What's the best way to lower 6 volts to 5 volts?

Hey friends!  I have a question. I want to be able to use 4 AAA batteries (6v) to power an IC. The IC's max voltage is 5.5. Is there any kind of way I can use two resistors as a voltage divider to lower the voltage 1 volt or should I just use a diode(which would lower it by 1.4v)? Thanks!

Posted by HavocRC 4 years ago


i have a battery just say 1 volt 1000 mAh and charge it with another battery 2 volt 1000 mAh how long will it take? Answered

How many mA go from the battery to the other? how do i calculate this??

Asked by ismael01 6 years ago


Too many volts from a bike generator

I took a treadmill motor and hooked it up to an excersize bike in order to charge a 12v battery and power an audio system.  Unfortunately, it worked far better than I ever hoped and is pumping out 75v at a max pedal, 45v on an easy ride.  I've looked into various charge controllers, but they only charge batteries close to the input voltage, and step-down voltage changers take it directly down to 12v, too low to charge a 12v battery.  Any suggestions?  Thanks.

Posted by EastsidePrep 6 years ago



What is the simplest and most efficent way to convert 3v to 5v?

There are several circuits out there on how to up-vert a 3v input to a 5v input, hwever I would like to know the simplest way.

Asked by Sargebubbles26 5 years ago


Battery power

I am attempting to calculate my amp need for my garage in order to set up a 12v battery system. Using the formula; Watts / voltage = amps drawn, I have hit a question. If using a 12v battery system and converting to 110v, should I be using 12v or 110v in the formula?Example; 100 watt light bulb / 110 volts = .91 amps. Nice!But if I use the 12v; 100watt light / 12v = 8.3 amps.I'm believing I would be drawing 8.3 amps from the battery to power this light.Plus the converter draw...Please tell me which is correct?

Posted by olddawg 10 years ago


Relationship between volts and amps

I'm working on a project found in this thread https://www.instructables.com/community/Solar-powered-cell-phone-charger-case-hack/ I think I'm almost ready to buy parts and start building but I have a small issue with getting the exact voltage and amperage output I need. I've been researching for hours and I can't find a simple answer to this problem. As I understand it, as voltage decreases, amperage increases to compensate and maintain wattage. Working on this basic understanding I've come up with this model. If I have a solar array consisting of 6 PV cells (1.5V 50mA ea) wired together I get 9V and 300mA. This is too much voltage and is on the low end of amps I want. If my math (and understanding of the subject) is correct, then if I use a 5V voltage regulator I will have a final max output of 5V and 433.3 mA which is right about perfect. Am I doing this right or is there more to it, like how I'm wiring the cells together? Am I correct in the idea that using a voltage regulator will increase my amp output? I'm not schooled in electricity in any way so I would appreciate any help I can get on this in as simple of a form as possible. Everything here I've put together from several hours of studying sites on solar DYI and electricity. Thanks. For reference, these are the solar cells I was referring to: http://cgi.ebay.com/High-Efficiency-Solar-Cell-32-22mm-1-5V-50mA-0-075W-/320541888508?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item4aa1c90ffc#ht_2428wt_1148 *EDIT* Below is a diagram of what I suspect may give me a 5V/490mAh output which would be absolutely perfect. I need to know if I can wire two different sizes of solar cells together in this manner and how it will effect the output.

Posted by HittingSmoke 8 years ago


Tiny circuit to measure amps?

I am going to use a ATTiny43U to obtain the voltage of a 2vdc solar battery, via self powering (0.8-5.5VDC). Using ohms law I know I can obtain the amps as I will have the voltage and a resistor. I want to know what resistor to use? I will feed the amps result back into the ATTiny43U as well as the temperature from another sensor. Can someone please advise me what tiny circuit I can use to get the amps as I do not know what size resistor to use? The operating voltage should be between 1.55 and 2.67 vdc give or take a bit. Thanks and kind regards, jB

Asked by britesc 5 years ago


How can I make a 9 volt shocker?

Okay.I want to build a shocker with a nine volt battery.No soldering iron.I have lots of 9 volt batteries. Note:A 9 volt shock is wanted .Not 300 volts. Thanks,bylerfamily

Asked by bylerfamily 9 years ago


I have a small fan that I want to hook up to my usb port...

but it's a 12 volt not a 6 volt, and it runs to slow on 6 volts. what do I do?

Asked by oldanvilyoungsmith 9 years ago


How many Volts come out of a USB plug, i mean the female part not male? Answered

Need to know soon, it's for a project

Asked by cd41 9 years ago


boost volts deflate amps? Answered

I recently came to know about a "mintyboost" from "steveastrouk"( a very helpful and trusted member of instructables).It boosts up volts while bringing down amps very much like a step up transformer.Well I've got 2 AA rechargeable batteries rated 1.2 volts and 1900mAh.So here's my first question-I connect these batteries in parallel and they give out a total of 2.4 volts okay fine....but what about the amps?will they get added up like volts and produce 3800mAh current?The latter part-I need to boost this 2.4 volts to 5 volts by bringing down the amps(any value is fine as long as its above 0.7 Amps).Could you please give me a specificated instruction on how to do this?If to use a "mintyboost"what software should I use to calculate the required values and......... the rest...... Pls don't think I'm lazy.I really want to do this so badly...

Asked by Adarsh_tronix 5 years ago


What's up with this transformer!

Hey I have a litte problem! (sorta, not yet!) So, I have one of those wall adapter things, and it says it outputs 12vDC and 1 amp. Out of curiosity, i hooked up my volt meter to it and the output was a whoppin 20 volts! Why was it 20 instead of 12 like the transformer said? This is making me worry about my other ones!

Posted by HavocRC 5 years ago


HELP please!! with Li Ion battery

1 st question: i have a 7.4v 2200mA li ion battery. my ip camera takes 5v 2amps what color resistor should i use and how many ohms? 2nd quesiton: i have a class 2 battery charger 12 volts 300mA is it good to charge my 7.4v li ion battery?

Asked by dwstar79 6 years ago


Question dealing with high volt capacitors in series

As we all know (at least most) you can get free cameras at places that recycle disposable cameras. After having my fun hooking then in parallel to attempt coil gun, or just melting holes in water-filled soda cans. But I wanted to try to hook some in series, so instead of 320V, i got 640. I know series adds up so both are fully charged to 320V, but heres my question. 1: Can they ever blow seeing that the output is 640 yet their rated 320? 2: If i discharged between then, can i have a greater chance of them exploding comparing to parallel hooked?

Posted by Killa-X 10 years ago


**HELP** PSP: battery charger **HELP**

Can I charge my psp with 6 volts (aka 4xaa) ? even though its only supposed to have 5v....Or do I have to go to the source ( what used to be radio shack in Canada ) and find a regulator. If so what little digits should be on it ? and would any of the following regulators work ? AN6541 IRL3103 ( I already have them I ripped them of of old mobos) To explain I lost my wall charger and usb charge don't work unless its on..... and the battery is dead

Posted by littlechef37 10 years ago


LED Voltage indicator

I have recently installed a solar panel in my garden to charge a 12volt 21Ah battery. I would like to show it off a bit by using a simple LED display to show it working. What I was thinking was to have a range of about 8V-25V. At the low end would be blue leds (for cold) up to red (hot) at the high end. Does anybody have any idea how I would go about getting something together. I can read circuit diagrams at a push (my Dad's the expert) and would like as much information as possible. Would it be possible to have 1 LED per volt ? Am I being simple? Would this project be self defeating in that it'd use lots of the free power I'm trying to collect? Any help anybody can give I'd be grateful to receive. Share & Enjoy. Zippy.

Posted by bunglesmate 10 years ago


how does voltage affect leds and charging batteries? Answered

Assuming amps are the same how would a different voltage affect powering an led or charging a battery and im assuming there's an upper limit and if so, r u able to find it out without a data sheet (since leds pretty much never have any markings on them)?

Asked by the judge 8 years ago


How do you make a kodak tazer with less zap?

I've read a few of the kodak tazer instructables, but none of them tell you how to suppress the voltage output (other than putting in a half-dead battery). But is there any way to suppress the zap? Cut it in half maybe? My history teacher is always wishing that tazer's were legal in school's, but this also looks very interesting, I wouldn't mind using it as a prank, but again, with less umff...

Asked by Insect 9 years ago


Electronic Box Lock Help!? Answered

OK so I would like to use a solenoid to unlock a box from the inside, problem is the electronic circuit I designed inside the box operates on 3 vdc and as far as I can tell most solenoids operate on a voltage of 6-24 vdc. Is there any way to make a simple driver circuit for a solenoid so it can operate on 3 vdc?  Below is a copy of the box's circuit so far. I would like the solenoid to be in parallel with the "puzzle solved LED."

Asked by TXTCLA55 6 years ago


How many volts is an IR LED? (from a remote)? Answered

I am trying to wire IR (Infrared) LEDs, and I need to know how many volts each one takes, they are from remote controls.

Asked by shammallamaman 9 years ago


If I have a solar panel that gives 6 volts, what kind of capacitor should I use?

I have never used capatiors and I've read about them. But I'm not sure what is the right kind to use.Heres what I want:solar panel (6 Volts) --------> Capactior ( What kind?) --------------> 2 way switch -------------> 6 volt LED

Asked by TNEN 9 years ago


How do I make a 160 DC volt power supply? Answered

Alright, for a science project I need a 160 DC volt power supply.  How do I make one? NOTE:  I hve the basic electronic skills and the system needs to be relativly small.

Asked by Kalrag 7 years ago


I need to run something that is 2 Volts off of my car battery, how can i most efficiently reduce my voltage?

Can i make a step down transformer that will reduce my volts from 12 to 2? However it needs to be able to handle about 40 Amps.

Asked by thagen 9 years ago


Good 300 volt coil gun capacitor charger?

I am creating a coil gun and have run into the problem of camera charging circuits taking to long to get the capacitors to the right voltage. Any suggestions on making a similar charging circuit on a larger scale or something similar that will run off anything between 1.5 to 12 volts? Any help would be greatly appreciated!

Asked by nms22 6 years ago


HOW TO: change USB plugs for 5 volts Jacks switch-Inputs (pics)

We have a several pair of carbon fibers pads, but what happens now all of them have a USB plugs that don;t fit with the receptive Jack Plug in 5 Volts Battery This batteries with the pads work to heat blanquet. We need help, or more than this a teacher! who tell us how to take out these USB plugs, how to join their cbables, and the how to add a plug in 5 Volts Jack. If is not clear please let me know Maria

Posted by Maria SoledadD 1 year ago


need some basic help with resistors and arduino

I'm just starting an arduino uno that I got for christmas and I have almost no electronics experience. I have a breadboard that can give me 6 volts, but what type of resistor do I need to get 5 volts out of it, or is it possible to split the 5v pin on the arduino board. What I'm trying to do is recieve an input from 2 buttons. I tried searching for it on google and found nothing. Let me know if I posted in the wrong section too, because I wasn't quite sure if the Tech section is right. Thanks in advance.

Posted by Nannerman 6 years ago



Low voltage AC?

How can I make a simple circuit that will produce alternating current using 1.5 to 9v power supply? This is an experiment for using an AC voltmeter - that is, making the needle move.

Asked by brandegor 8 years ago


What type of battery would I need to power 10m of RGB LED strips? Answered

For the summer, I would like to run two 5m strips of RGB LEDs in the cabin of my boat. I dont particularly want to run it off of the boat battery because I do not want to rain it while stationary. So my question is what type of battery, what specs, should I be looking for? Obviously a 12 volt battery because that is what the LEDs run off of, but is there a certain type I should be looking for, one that can handle the amount of amps the LEDs draw. Also if you could provide a link to a specific battery that would be helpful! The specs for the LEDs: Run off of 12 volts, (2) 5m Strips, approximately 5 amps per 5m -- so 10 amps total  Link to RGB LEDs: http://www.amazon.com/gp/product/B00ASHQQKI/ref=s9_wish_gw_d5_g267_i1?ie=UTF8&colid=2YTJAFKDJWBSM&coliid=I2PXDOU6G8R0XG&pf_rd_m=ATVPDKIKX0DER&pf_rd_s=desktop-1&pf_rd_r=1PT4GDRNRM4JE2691CXW&pf_rd_t=36701&pf_rd_p=2079475242&pf_rd_i=desktop All suggestions and help are truly appreciated!

Asked by cobrien2115 3 years ago


Arduino Solar Capabilities

So I went and bought a 1.5 Watt 9v solar panel from radioshack today. It gets ~10.5v and ~80mA in full California sun, and ~10.2v and ~75mA in afternoon light. Does anyone have any experience with running an arduino only on solar power? If so how much load can it take at this power level?

Posted by martzsam 5 years ago


Could I connect 2 or more USB ports together to light several leds? Answered

I'm planning to make a modified version of the led music box that is hopefully powered via USB. I'm looking to use between 10 and 15 leds. Is it possible to get this kind of power from USB ports?

Asked by Ovrlrd 7 years ago


I need 9V DC what happens if I USB it?

I'm making a compact speaker enclosure that will fit in a laptop bag I've got everything together and looking sweet. making this because my ACER laptop has crappy sound and I want to be able to hear things on it when I travel. I have sick speakers at home but there very not portable. problem right now is power is supplied by a 9V DC adapter I really hav no mre room to make any other type of circuit or battery pack........its pretty tight. what happens if I just cut the adapter and put a USB end on it? I realize it will only provide 5 Volts but will it work?......... maybe just reduced power? will any damage result? I know only a little about voltage and most of my electrical experience is through trial and error. (not recomended, I've zapped myself more then a couple of times) Ideas?

Posted by chaoscampbell 10 years ago


How do you wire a battery pack to split the voltage to multiple electronic devices?

I am wanting to use a two battery packs (a 9V and 12V) to power a few small electronics for a Halloween costume... From the battery pack, I would like to split the power to run into multiple on/off switch buttons that will control the current to small PC fans, small speakers, and a small 9V amp

Asked by 8 years ago


Can I hook up power and usb cable to arduino?

Hey guys, When I'm using my arduino, (plugged into my Mac via USB) my mac just randomly shuts off. Is it because I'm pulling to much out of the USB? Can I hook up my 9v into the DC plug and hook up the USB or will combine the input and fry the board?

Posted by HavocRC 5 years ago


Transformer Question? Answered

Hi, I want to plug this transformer I have into the wall to be able to use its output to power several of my other projects. I need a way to limit the current from the mains power supply into the transformer, it has to be limited to about 1/2 an amp. I really don't want to lose any voltage though, and when I use a resistor to limit the current it sucks down all the voltage and overheats. I really need some help with this. Thanks

Asked by transistorguy 7 years ago


we dont have 5v on usb after shutdown, why are we trying to power it from psu if psu has no powerout after shutdown?

We dont want power on usb port after shutdown we connect it via molex molex after shutdown doesn't have power too? if we dont want to supply 5vdc from usb after shutdown, why are we connecting it to PSU which doesn't supply 5vdc after shutdown either?

Asked by w477s 8 years ago


How do I regulate voltage on a multi-amp battery charger.

I know very little about electronics. I have a car battery charger that outputs in 12 voltsDC. It is also "switch" selectible for 2 or 10 or 50 Amps. Once I select one of these choices 2/10/50, I would like to vary the voltage up and down from 1v to 12v. How do I build something that will vary the voltage at each of these amperage levels. Thanks- Steve

Posted by st600r 9 months ago


Is this DC motor suitable for a wind turbine/bike generator?

Hi, so I have recently salvaged an old garage door motor, I have managed to a separate the DC motor from the casing and now I am converting it into a generator (by removing the metal core and replacing it with permanent magnets.) The motor's label says 120v, what can I make with a motor this size? Will this motor be acceptable to convert and make into a generator for wind turbine or bike? Label: THE CHAMBERLAIN GROUP INC. MOTOR No. 123D67 120V 60 Hz 4.5A 70 degrees C INT. DUTY THERM-PROTECTED  TYPE T. (CL. B (Odd symbol) OBJY2 188B72) ASSEMBLED IN MEXICO Thanks guys!

Asked by Exploitation 4 years ago


What does the connections on this switching power supply mean? How do I get power to it?

I have this power supply and I don't know how to use it with my LED lights. I don't know what the connections on it mean. I assume I need to connect it to an outlet at some point but I am not quite sure how to do this in a safe and proper manner. I need some basic newb level directions to do this. I am in a bit over my head with this stuff. I expected it would just be more plug and play. Here is the power supply and the connections in which I don't completely understand. I just cant afford too much time to dig in completely into learning everything right now. I think this is the pdf of the power supply: http://dl.dropbox.com/u/655465/s-60-spec.pdf Thanks Josh

Asked by joshuarule 7 years ago


What's up with Amps, voltage and current?

So I'm having trouble finding out where amps come in. Typical batteries (AAA,AA,9v,3v) don't say the output amps, just output voltage. But things like RC batteries, and wall transformers have a specific amperage output. So say my LED and 9v battery. I know I need to use a 150 ohm resistor. Since resistors limit current, then is there still 9v going to my LED its just the amps/current that being lowered before going into the LED? If resistors limit current, or in its unit of measure, amps, then my LED is still getting the supplied voltage just a lowered amperage?  How do I know how many amps my projects are drawing? How will I know if my DC wall transformer with 12vDC and 1 ma isn't going to fry my circuit? How would I know if 1 amp is too much or not enough for any my circuit? Please help, none of this makes sense, ~electricloser  

Posted by HavocRC 5 years ago


Coil Gun Project

Hey guys, I am currently building my first coilgun, first of all, the components: Charging:     Disposable camera circuit x 2     2 x D cell batteries Capacitors:     2 x 1200uF 200V     2 x 680uF 200v     2 x 300uF 200V     1 x unknown (attached to camera circuit with no info) Switch:    250V @ 15A - 6 pole toggle (I will upgrade to some for of solid state when I have the money) Now, because I have two of each capacitor I have put one of each into a parallel bank, giving me 2 cap banks with one of each cap, I then connected the two banks in series, I have not done a lot of maths yet which I think I should but I was hoping that would give me 400v which seems to be average. The problem is, it is only charging to 340v tops, I think that may be due to the camera circuits being wired incorrectly. I have the two batteries in series, both charging both of the circuits, then the circuits both charge the caps, the + and - outputs meeting on the caps, am I doing that wrong? Also, does having 300uF caps in series with 1200uF caps hinder the bigger ones? Would I be better of with just the 1200uF and 680uF, or maybe even just the 2 1200uF in series? should I also leave the small cap on the circuit or take that off? Thanks in advance guys, any help would be greatly appreciated. I am having a lot of fun with this project and while I wouldnt like to be on the other end, it is still not as powerful as I would like, even for it's small size.

Posted by TristanD27 4 years ago



DIY airconidition running on 18 Volts?

Hello, i'm building an mini airconditioner for my room. i have a box with 2 computer fans on it, one for input air and one for output air. the box will be filled with ice, and it should work. for the powersupply i use an old printer powersupply, which gives me 18 Volts. but my question; im not realy sure if i can run the computer fans on 18 volts for a long time. i tried to run them for a couple of minutes, but im not  really sure. who knows?

Asked by ingkiller 6 years ago


SSR and a hotplate

Dumb question. Have a heating plate that uses 1100 watts and runs on 120 volts ac. if 1100 watss / 120 volts = more or less 10amps, Could I safely use a 10 amp rated ssr aka solid state relay or use something higher.

Posted by Computothought 3 years ago