battery backup

I have a really cool sunstech weather station but when the power goes off it loses time date and weather prediction. I live in Spain and we are prone to daily power cuts. I need a low power 5v back up system to power it. Any ideas welcome

Posted by malchall 4 years ago | last reply 4 years ago

-5v Voltage Regulator

I want to make a -5v Voltage Regulator... Does anyone know if I replace the 7805 regulator with a 7905 would that be enough, or would the capacitors have to be different values?5v Voltage Regulator Schematics

Posted by mrshow555 10 years ago | last reply 10 years ago

5v relay module with tv usb

Hello there! I'm sorry if someone already asked this question but I can't find it! I would like to connect 2m led strip to my tv usb so it turns on and off with tv. Can I use this kind of relay (;=item5b016763a7 ) to do it?  Thank you in advance!

Posted by tosho82 4 years ago | last reply 4 years ago

"5 volt limit" circuit? Answered

Is there a circuit that will take a range of voltages and make all of the voltages that are over 5 volts be 5 volts  like so: 3.5 => 3.5  4.2 => 4.2 4.9 => 4.9 5.1 => 5.0 6.3 => 5.0

Asked by flybye22 8 years ago | last reply 6 years ago

Where find 5v regulators?

Hi!Where can i find 5v or 12v voltage regulators?

Asked by ondrikczech 6 years ago | last reply 6 years ago

5v to 12v convert

Hello, I want to connect a portable solar powered rechargeable to 2 DC fans of 12v to cool my car. 1. I have 2 options of portable solar powered: (A) 1500mAh, outputs: 5.5V / 800mA (B) 2000mAh, outputs: 5V 500mA     which one is preffered to connect to those PC fans? 2. most of the PC fans are working at 12v. I don't quite sure if I'll build simple 5v to 12v regulator it will works and produce enough airflow. Thanks.

Posted by ashakif 7 years ago | last reply 22 days ago

Pulse circuit?

I need to make the circuit that every time it charges the capacitor to a certain voltage (e.g. 5v or 12v) it discharges it

Asked by Dantex 8 years ago | last reply 8 years ago

5v to 12v step up

Hi, I am looking to power some led's by USB. Problem is that the led's are 12v. Here are some example led's:;=item43a76471ea#ht_3932wt_1396 Would something like this do what i want it to do?:;_source=gbuk  Also looking at the step up booster i have no idea where i would solder/connect wires to the device? Any help would be appreciated. ItzMar

Posted by ItzMar 6 years ago | last reply 6 years ago

covert 3V battery source to 1.5 V

Hi Guys, I have a 3V battery source and want to convert it to 1,5V to run a device. How do I go about doing it? Will a voltage divider work accurately?

Posted by kurtselva 5 years ago

How to get 5 volts from 4xAA batteries?

Hi all! Whats the best way to get a nice circuit friendly 5 volts from 4xAA batteries? Measuring some brand new AAs, they're about 1.6v when new, which drops under load, I know. So four AAs of course add up to 6.4v, possibly blowing my low current circuit. And isn't a 7805 voltage regulator only good with aroundabouts 7-8 volts source because of how they work? Plus DC-DC converters are expensive, and resistors are wasteful. :-) Thanks!

Asked by Heliosphan 8 years ago | last reply 6 years ago

How can I convert 12v down to 5v? Answered

Asked by niranj_1994 9 years ago | last reply 8 months ago

Help! (5V psu problems)

Help!I'm trying to make a 5V psu for programming my new (but not so shiny v_v) ATtiny2313'sI've got the circuit shown below set up, but I'm getting out around 5.6V, when the spec sheets say that I'm supposed to be getting out 5V (+/- .2V) I'm using the LM 340t5, just 'cause I don't have any other regs (except for the MC78M05CT, which is basically the same thing.Any Ideas?!EDITI know what was wrong - it was my meter, it really was 5V all along ;)

Posted by T3h_Muffinator 11 years ago | last reply 10 years ago

12v and 5v Power Supply from 240v Answered

I am creating a home automation device that uses an arduino. The devices are connected to a relay. The real problem is I am using a using a DTMF decoder with the relay, while the relay works only with 12v power supply the DTMF decoder works only on 5v input (USB from computer to arduino). The devices that I know of are capable of converting a 240 v to 12v or 5v not both. What should be done so that I am able to get a 12v and a 5v from a normal 240v household power socket?

Asked by NirmalMRaj 2 years ago | last reply 2 years ago

in where do I find and how do I tell if it is a 5v regulator?

I need to find a five v regulator(7805) for a portable 9v battery charger and i cant go out and buy one. can someone tell me in what device i can find a resistor(specifically 5v).  And i need to know how to tell if it is a 5V Regulator. heres one i found.. does it look like a 5v?                                                                                                                                                                                                                                                                       thanks,                                                                                                                              The DoctorOfAwesome

Posted by Dread_Neck 8 years ago | last reply 8 years ago

Converting 12v DC to 5v DC

Greetings, I’m very new in electronics. I would like to connect my analog camera that uses 5v dc to my car battery. So I need your help to make a voltage converter. From what I have understand searching the web, I will be possible and very easy actually. All I would need is an opamp and some resistors?!!! Right? So any diagram or anything that you can help me with will be more than appreciated. Thank you for your time reading this. Best Regards P.S. I hope I’m in the right place writing this topic  

Posted by toqilula 8 years ago | last reply 7 years ago

Can I power a monitor from 5 volts?

Even if I have to open it up can I run this on 5v using a buck converter or by modding the screen? The screen is a RCA DRC69702 that came with a dvd player and all I want to is power it freom a two port battery. one port will be hooked up to the monitor and one to the raspberry pi.

Asked by nerd7473 4 years ago | last reply 2 years ago

How can I multiply/double (or just increase) voltage in a DV 5v curcuit ???

ok i have the following parts to ue for this: (all leftovers from former project..)  :) 1x mosfet IRF510 power transistor 5,6A 100V 9x 2N3904 amplifier transistors 40V 0,2 A .0.625 W ~16x 1uF capacitors 50V ~99x recifier diodes 1A 50V ~35x 2k resistors  0.25 W the idea is to charge a battery pack consisting of 4x 1,2-1,25V = 4,8-5V 3000mah AA nimh batteries using my 5v usb wall charger that has 1A output! i tried connecting the battery pack directly to + and - and 'i think' its starting to charge but after 1-2 hours at full rate (5v 1a) it should be at least 50% charged (3 hours would be full charge -> 5W x 3 = 15W), but if i connect them they last for about 2 -3 minutes and then empty again!! so after this im concerned that i might need at lest 6V-10V to achieve the desired effect !!  -> charge 15W NIMH batterpack with wall charger (nokia ac-60e.. 1-1,5A) i nless than 3 hours (as like a phone would need !!) therefore i need a cuirciut (ONLY DC) to double my 5V OUTPUT to 10V (yiou shouldnt apply more than twice the curent of a batter pack) or ideally 6-7 V but i dont know if thats possible without a swiching IC or more different resistors.. so just doubling would be nice at the moment!!  

Posted by sblocc10 1 year ago | last reply 1 year ago

9V-12V from portable battery to usb hub?

I have a portable battery: I would like to run the output labeled DC9-12V (or DC16-20V) to a 5v/2.1a usb hub that I have.  I was thinking I could strip down a 12v usbhub car charger, but I wouldn't know how to manage the connector.  Has anyone done anything like this? Thanks

Asked by 9zpvwz 8 years ago | last reply 8 years ago

What should I power my rc car based robot on? it uses 6 1.5v batteries.

I have an erector rc car and i am using all of the interior components. The system runs on 6 1.5 volt batteries, and i want to reduce the amount of space that takes up. is there any other sort of battery(s) equel to 6 1.5volts?

Asked by remo2 6 years ago | last reply 6 years ago

What are possible uses for weak batteries? Answered

A followup on my previous question, sort of... I have about 150 old semi used 1.5v AA batteries that don't have enough juice in them anymore to power anything significant. One can only have so many Joule thief powered LEDs, and it's a shame to dispose of them all.  So the question is, what would YOU do (*Pointing at you!*) with those batteries? Thanks for any and all suggestions! P.S. Please provide an instructable if applicable :D

Asked by Morgantao 5 years ago | last reply 5 years ago

fast and easy way to get 3.3v from 5v without a lm317? Answered

I got a dvd player but the power supply was missing. i can get the 5v and the 12v, but other than a lm317 (which i dont have) i cant get 3.3v. ive looked at all sorts of things to try and find a 3.3v regulator, but everything i have searched up lead to several misleading results. so i was wondering, what value resistor could i use to get 3.3v from 5v or what devices could i look in to find a 3.3v regulator? i have several computer motherboards, a bunch of cd drives, a couple hard drives, etc. please help! thanks in advance,           zack247.

Asked by zack247 7 years ago | last reply 6 months ago

LED USB light cant run with 5V 1A usb charging adapter?

Hello Friends, I cant understand why USB LED not lit up.  when I insert in to PC usb port, it runs nicely. but when I insert in usb charging adapter and try to run. it cant. does it require few mili amps? cant it take few mili amps form 1Amp?  

Asked by supertechey 3 years ago | last reply 3 years ago


Tbd392nr lcd inverter

Asked by yhdesai 4 years ago | last reply 4 years ago

How do i make a 1 amp boost converter that converts between 3-5v to 5v?

Hey, so  have been buying pre built boost converters but i wanted to build my own, my question is, how can i make a step up boost coverer circuit that takes between 3 and 5 volts and converts it to 5 volts at 1 amp. In you answer could you explain what each part does? Thank you!!!

Asked by jbdawinna 4 years ago | last reply 4 years ago

Arduino Mega 2560 timeout? Answered

I have tried uploading the simple "Blink" sketch onto a 5v Mega Pro from Spakrfun using their 5v FTDI programmer. Despite my best efforts I have kept getting this error... Binary sketch size: 1,632 bytes (of a 258,048 byte maximum) avrdude: stk500v2_ReceiveMessage(): timeout avrdude: stk500v2_ReceiveMessage(): timeout avrdude: stk500v2_ReceiveMessage(): timeout avrdude: stk500v2_ReceiveMessage(): timeout avrdude: stk500v2_ReceiveMessage(): timeout avrdude: stk500v2_ReceiveMessage(): timeout avrdude: stk500v2_getsync(): timeout communicating with programmer I have know I am using the correct COM port and I have the right board selected. I have tried to re-install the driver but to no avail. Nothing I have found online has worked.

Asked by GenAap 5 years ago | last reply 1 year ago

Joule Thief Toroid not helping to step up, Why? Answered

Hey fellas..I am having problems with joule thieves especially with the toroid part.... First time I wound my Ferrite Core and the joule thief ran smoothly... But recently I had to unwind it to try other wires which didn't work.. So i again wound up the toroid just like the first time when it used to work but unfortunately this time it didn't work... I have checked everything and found that the only problem is that the toroid is not helping to step up the voltage.. When i applied 9V across it, the LED glowed but for 1.5V it didn't. So there is a problem with the toroid.. But what it is and why is it happening I don't know..I mean for the same core and same style of winding once it worked and now it doesn't, Why ?? Can anyone help me ??

Asked by Arijit Chatterjee 4 years ago | last reply 4 years ago

will 5v stepper will work on 12v?

In ""   the datasheet for pl15s-0120(Stepper of dvd drives) says it operates at 5V , Didn't the a4988 gives 12v out ? , will it gonna work ? (posted comment there but no one replied .....)

Asked by _Boltz_ 3 years ago | last reply 2 years ago

How to create dc input to dc 5v and 12v (two outputs) circuit? Answered

I need to create a circuit with two different output voltages but with a single input voltage. The output voltage must be 5v and 12v dc. The input voltage must be max 12v dc (for using 12v dc power adapter from ac mains).

Asked by akki5230 4 years ago | last reply 3 years ago

How do I charge 4x AA batteries using USB? Answered

I'm planning an internal laser sight mod for a Maverick Nerf gun, and I've bought a cheap 5v laser module from eBay. I plan to fit a near 5v rechargable battery, or 4x 1.2v AA batteries, but from my understanding of battery chargers, would the USB's 5v be to low to recharge them (The charging voltage seems to be consistently 150% the batteries' output voltage for all my electical devices).

Asked by Shadow Of Intent 6 years ago | last reply 6 years ago

How to make it work? USB + 5V rechargeable battery + 12V LED strip!

I want to an LED Strip that works my USB or Battery, I got the battery and the USB working fine, the battery charges up without problems, but I need to light the LED Strip (12V) with a 5V battery. Is there a DIY way to: -Step up the voltage, or -Step down the LED Strip Voltage. I know each SMD LED works around 3V, but I can't make sense of the wiring and resistors on the Strip, to wire the SMDs in parallel.

Posted by RaptorHunter 4 years ago | last reply 4 years ago

How do you use a voltage regulator? Answered

               so this question is pretty straightforward, I'm trying to build a standalone ATX type power supply.  I'm using an Xbox 360 power brick, so I will have plenty of power, however the 360's power brick only has 12V out available.  There IS a 5v rail but only the 12V is available because I'm using the 5v to enable the brick.  And if I draw any more current from the 5v rail I overload it and it shuts the brick off.  Plus the 5v rail is only 1 amp so it doesn't even have enough power to run a DVD drive. (actually broke an old one testing it :P)  So, what I want to know is how to use a voltage regulator to scale down the 12V rail so I can have 5v and 12v to use standard molex devices with.  Also If anybody knows of a particularly beefy regulator i might use (5 amps maybe) I'd love to know :)

Asked by junits15 8 years ago | last reply 8 years ago

whats so hard about charging liithium ion batteries? Answered

I am charging my cellphone. its an android. the charger for it says the output is 5v 700 mA. i am using a  wind turbine or solar panel or both connected to a 5v regulator. and some capacitors. should work right? i will keep a close eye on the phone checking the phones battery indicator to see when it is completely charged to avoid overcharge

Asked by ismael01 6 years ago | last reply 6 years ago

How to step down a 12v DMX LED Controller to 5v?

Hey i currently have an "Abstract MFD-10" DMX controller that i want to run 64 LEDs/2meters of "LPD8806 +5v Strips" off of. DMX Controller= Led Strips= How do i step down the 12v supply to 5v while maintaining the flow to keep the strips running effectively? If you give me the formula for it i can work it out myself and will post here with what i worked out as i enjoy doing my own workings but i am a bit lost with this. Also I am willing to simply change a component in the controller itself if this would be easier and cleaner (No external boards/components) Need anymore info just ask.

Asked by Pathogenex 4 years ago | last reply 4 years ago

what is so hard about charging a lithium ion battery? Answered

I am making a wind turbine charge my cell phone. my design will use a hand made wind turbine using an electric motor. hooked upto a 5v voltage regulator. with some capacitors. if it is putting out 5v i know it will charge right? i heard of batteries messing up.  i will constantly monitor the phone too see when it is charged..according to my phones battery indicator

Asked by ismael01 6 years ago | last reply 6 years ago

Charge my sony ericsson with my iphone charger?

Hello How do you do if you want to charge you sony ericsson cellphone with an iphone 3gs charger? If you plug your sony ericsson with an iphone charger it will act as if it´s plugged in to the computer and not charge. It´s because the iphone charger puts out voltage on the data pins, how do I bypass this? If I only hook up the VCC (5V)and Ground (not the data pins)the charger does not begin to charge my sony ericsson. What should I do? connect the data - and data+ to each other? Info: Sony ericsson w580i 5V charger Li-Polymer 3.6V, 930mAh

Asked by Popstickal 8 years ago | last reply 8 years ago

How it is possible to power up a 12V device using only 5V?

I had a power outage some time ago, and needed to use the internet for university search. i was with my notebook, EEEPC 1000H with 4 hours of batt. my internet is over a cable and it uses 12V for power; i had a cable for my external dvd reader (ad/dc pin to USB)that fitted into the modem, and i plugged it into my usb. it worked very well. however, the notebook started to heat up slowly, and the battery indicator dropped from 4:00 to 2:00; this was safe to do? could it damaged my notebook? how can be possible 12V into 5V?

Asked by Shiron 9 years ago | last reply 9 years ago

Powering up an old IDE hard drive externally?

How can I make an old 2.5" laptop IDE hard drive spin up with out a computer? I tried connecting 5v to pin 42 (+5 VDC (Motor)) and 0v to pin 43 (ground) but the drive does not spin up, it just draws around 270mA from the supply. How can I get the drive to power on? do I need to short out some other pins too? What about the jumpers? I am guessing it needs some sort of "power on" signal but I am unsure how to give it this. I am NOT connecting this to a computer BTW, I do not need to read any data. Just for the motor to spin up to have some "fun" with. Thanks.

Asked by Alex1M6 6 years ago | last reply 4 years ago

Joul thief how to? Answered

I've been reading some ibles about joul thief making, and most of them teach how to power an LED with a 1.5v AA battery.  That is great, if you want to power an LED with a 1.5v AA battery :) But what if I want to keep using old, weak AA batteries, as 1.5v batteries?  How do I make a joul thief that takes whatever the battery can give it, and outputs it as 1.5v?  I know the kind of transistor, ferrite core, number of windings and wire gauge all affect output, so how do I know what to use? Thanks!

Asked by Morgantao 5 years ago | last reply 5 years ago

3.7v to 4.5v how ? Answered

I have an wireless game controller which runs on 3xAAA(4.5v) battery... i also have plenty of spare li-ion 3.7v batteries upto 1000mAh.. so what i'd like to do is install that rechargable li-ion battery into my game controller... so i dont hv to buy AAA batteries every time...pls guide me how... and pls tell me as simple as possible... because i live in india..n small electronic parts like resistors,regulators etc. are reallyyyyyyyy hard to find here... thank you in advance...

Asked by D3zire 4 years ago | last reply 5 months ago

If I put 5v in a 5v voltage reg, will 5v come out?

What kind of voltage drop should I expect if I put 5v in a 5v reg?

Asked by nepheron 9 years ago | last reply 9 years ago

5v and -5v from 9v? Answered

How can I get +5v and -5v from a single 9v PP3? Not 4.5v, I could do that easily with a voltage divider. Preferably using only passives and discretes (Inc. voltage regulators)?

Asked by andy70707 7 years ago | last reply 7 years ago

How to convert 12V to 5V for incar use ?

I need to create a cable that will run from my car battery into a device that runs on 5V DC power. It needs to look like this: INPUT: 12V car battery Simple bare +ve and -ve wires OUTPUT 5V 1.25A barrel connector 5.5mm (I beleive) like this one:

Asked by SamC17 3 years ago | last reply 3 years ago

Charge 2x AA batteries via USB - Voltage Question? Answered

Hi there,  I guess I didn't pay much attention, especially in some classes when I should have too :) I am DIY-ing a little project, and I need to charge two AA batteries (2450 mAh) via a PCB that get's charged via USB (5V),  here are the specs of the PCB:  Input voltage DC5V Input Current 2A Transmit power 5W Charging voltage 5V Charge Current 500-1000MmA My dilemma is - can I charge (both batteries together) safely with this voltage and current? I looked of course at some "usb aa chargers",but the problem is that i have no space for an extra pcb in the battery department. Thanks a lot if anyone answers, George

Asked by grancharov 3 years ago | last reply 3 years ago

Help with zener diodes? Answered

I'm trying to get a better grasp on how to use a zener diode. I have plenty of information about what they do (allow current to flow one way until the voltage is high enough, then reverse the flow), how they work and even how they are made, but finding basic information about how to use it is harder. I am trying to connect a Keyboard Encoder to an Arduino. The Encoder runs on 3.5v and the Arduino runs on 5v. When a pin on the Encoder is connected to ground it outputs a keystroke to the computer. I have an Arduino pin set to HIGH (5v) as normal and under some conditions it changes briefly to LOW (ground) which is when I want the Encoder to output to the PC, and then back to HIGH (5v) again. To protect the encoder from the higher voltage coming from the Arduino I think I need to use a zener diode. If my understanding is correct it should work as described in the diagram. When the Arduino pin is High (5v) the Encoder reads as 3.5v and any voltage over 3.5v is drained to ground rather than pushing against the Encoder. No keystroke is passed. When the Arduino pin is LOW (0v) the Encoder reads 0v, the zener diode adds resistance and voltage runs to the Arduino. The Encoder sends a keystroke to the PC. My main concern is that once the voltage is over the 3.5v all of the power will drain to ground rather than maintaining the 3.5v before the zenner diode. I can't find anywhere which will tell me either way. If you need more information on my set up please let me know. I'm really struggling to get my head around this! Thanks!

Asked by RandomIdeaMan 5 years ago | last reply 5 years ago

Using Arduino and 8 servos!? What type of power source? Answered

Hey Arduino guys! I got a question. I am using 8 servos with my Arduino. All the servos are hooked up parallel to the 5v and GND on the Arduino. All the control wires are hooked up on pins 2-9. I'm using 6 AA batteries as my pack. Is this OK for my Arduino? With all these servos moving at once, I want to make sure I'm not frying my board. Oh, and, got another question. The 6 AA batteries are too heavy for my robot spider, so I want to use two 9v batteries instead. But, this delivers 18v. Arduino and only go up to 12v. So, what can I use to bring my 18 volts from two 9v batteries down to 9v or 5v? What can I use? A voltage divider with resistors? A voltage regulator (whatever that is :P)? Thanks guys!

Asked by HavocRC 5 years ago | last reply 8 months ago

USB power? Answered

I have a 1.2 V nimh battery and a 3.7V li ion (no protection circuitry) battery, which would add up to 4.9V if put in series. However, I want to turn it into a temporary USB power supply (5V) so ignoring all the things regarding putting 2 batteries of different capacities together, is there a way to kick the voltage up a tiny bit? I was thinking something like filtering the output of a joule thief, possibly. I also have a solar panel (4.5V, ???A) and was wondering if that could help, but I don't want to rely on it too much.

Asked by .Unknown. 8 years ago | last reply 8 years ago

Wiring diagram of B0505S-1W 5V to 5V converter DC DC power module Isolation

B0505S-1W 5V to 5V converter DC DC power module converter 1000VDC Isolation. Need the wiring diagram of this component.

Asked by Sayan_trex 6 months ago | last reply 6 months ago

A 5V zener reduce the voltage in 5V or regulate it in 5V? Answered

I neede to know if a zener diode regulates the voltage or reduces it and also how can I know what type of zener it is.

Asked by tgferreira184 6 years ago | last reply 6 years ago

How can convert a12v down to 5v?

Asked by niru21 9 years ago | last reply 9 years ago