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)?

Question by andy70707   |  last reply


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.

Question by tgferreira184   |  last reply


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?

Question by nepheron   |  last reply


-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

Topic by mrshow555   |  last reply


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.

Topic by ashakif   |  last reply


50uV to 5V amplification

How to amplify 50uV to 5V using LM324n op-amp

Question by Pranay ReddyK   |  last reply


simple 5v regulator?

Today i made a shaking generator for a shaking flashlight.i am using a 5.5v 1F capacitor as storage device.but output of  the generator is 3v~6v DC.how i can regulate the output ≤5v?.i am looking for most simplest and cheapest method. can i use a resistor?

Question by vina1991   |  last reply


5v battery backup?

Hi, I have a 555 timer circuit running in monostable mode which I need a battery backup for.Anyone have a simple, reliable circuit that can achieve the following results :1. Switch power between the 5v cell phone charger and the battery in the event of a power outage. The "switch" needs to be seemless otherwise it will trigger the monostable as it is set to trigger or re-trigger whenever the power goes off and on again.2. Charge the battery when the power is on.3. Stop charging the battery when it is fully charged.Any other suggestions will be much appreciated. I am not rigid on the design and use of parts, although....the cheaper the better without compromising on reliability (of course).This is for a security system that drives two lasers, a camera and a cell phone. Not sure if the cell phone battery can be used to power the "backup system" as well as run the cell phone.Thanks in advance.GK ;)

Question by GhengisKhan1981   |  last reply


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

Topic by malchall   |  last reply


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 ( http://www.ebay.com/itm/5V-1-Channel-Relay-Module-H-L-Level-Triger-with-Optocoupler-for-Arduino-Raspberr-/390865576871?pt=LH_DefaultDomain_0&hash;=item5b016763a7 ) to do it?  Thank you in advance!

Topic by tosho82   |  last reply


"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

Question by flybye22   |  last reply


Where find 5v regulators?

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

Question by ondrikczech   |  last reply


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 ;)

Topic by T3h_Muffinator   |  last reply


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: http://www.ebay.co.uk/itm/12V-SMD-1M-60-LED-STRIP-LIGHT-RED-HOME-AQUARIUM-CAR-/290571186666?pt=UK_HomeGarden_Lighting_Lamps_Lighting_SM&hash;=item43a76471ea#ht_3932wt_1396 Would something like this do what i want it to do?:http://www.suntekstore.co.uk/goods.php?id=14002311&utm;_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

Topic by ItzMar   |  last reply


will 5v stepper will work on 12v?

In "https://www.instructables.com/id/eWaste-60-3DPrinter/"   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 .....)

Question by _Boltz_   |  last reply


4.7uF capacitor 5V or lower????

Do someone know where i can buy a 4.7uF 5V (or lower) in europe????

Question by Dannne11   |  last reply


help with 9v to 5v to 3

I am trying to make someting liek this guy made here https://www.instructables.com/id/EZQ7ZDDF0JY1JSH/ where can i find a circuit that will give me outputs of 3v 5v and 9v

Topic by DELETED_kclv1988   |  last reply


usb 5v to 3v fan

I'm considering running a 3v fan from a 5v usb. can i simply put adequate resistance in series to reduce current to acceptable levels?

Topic by Toga_Dan   |  last reply


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

Question by Dantex   |  last reply


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!

Question by Heliosphan   |  last reply


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  

Topic by toqilula   |  last reply


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?

Question by NirmalMRaj   |  last reply



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

Topic by Dread_Neck   |  last reply


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!!  

Topic by sblocc10   |  last reply


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.

Question by nerd7473   |  last reply


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

I have a portable battery: http://www.xpalpower.com/us/products/xp18000/ 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

Question by 9zpvwz   |  last reply


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?

Topic by kurtselva 


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?

Question by remo2   |  last reply


zener diode (limit 9v to 5v)? Answered

Can i use zener diode  to limit voltage from 9v to 5v? ( i would use 5v zener diode ) can this work? what else do i need to use? and  is this way efficient? i was thinking to power my phone with this or to charge my light

Question by tealk   |  last reply


I'm using a 5V boost regulator?

To charge a cell phone battery.  BUT maximum current is 200 mA.  That's not enough current I'm assuming, right?  I need a continuous output of 5V but my students are most likely not going to get 5V from a shake charger (neodymium magnets going in and out through a coil of wire) which is why I was going to use a LM7805 but that needs 3 volts more than the output voltage.  Any suggestions??  Thank you!

Question by mckywer   |  last reply


USB 5v step up to 12v?

Is there any such thing as a device that will step up 5v from usb and convert it to something else like 12v? I say this because I have a solar usb charger that charges a 2600 mah battery and outputs 5 v at 800mah to usb. i wanted to step it up so it could be used for other things.

Question by XBLmonster   |  last reply


Variable speed on a 5v brushless fan

Hi everyone! I have a 5v DC (0,15A, 50mm x 15mm) computer brushless fan that I want to power with a battery pack (4x AA rechargeables= 4,8v) or the MightyMinty Boost. This small blower is meant to be a part of a woodgas stove, and will bring air to the fire through a small duct. I'm looking for a circuit that would allow me to control the speed of the fan and the airflow. Kinda like a dimmer switch. Is there a readily available switch or devices that I could plug between the batteries and the fan? I guess the RC guys out there know a few thing about variable speed controller. I'm a newbie at this; I don't what to build a circuit from scratch, unless it's really simple. Thanks

Topic by jemor143   |  last reply


convert 5v DC to 3.3v DC?

Hello would somebody help me with this please, I am not much of a "electronic" kind of guy so this is a big problem for me. I lost the power adapter of our office router WRT54GC (linksys) and my boss has his finger cross on me. I only knew of its power which is 3.3volts 2A DC. From my location, it is very unlikely to obtain a replacement or an equivalent adapter. I have salvaged a power supply of and old printer that gives off 5.0V 2A DC but the router would not run with this voltage. I will really appreaciate it if somebody would be able to help with a step by step explaination on how to lower the 5v to 3.3V . Thank you very much.

Topic by gincasty   |  last reply


Looking for a 5V valve to be driven by ARDUINO

Hi everybody, I am working on a project to make an automatic watering system driven by arduino. I am looking for a valve which I could operate without any extra power supply but the 5V from the ARDUINO. It would be perfect if the valve could be in the range of the 6mm for tubes connections. As my project will rely on gravity for water movements, I don't want to use a pump or whatever active device. Just some standard batteries connected to ARDUINO. Do some of you know such a valve? I have looked on the net without any success. I have found loads of watering projects using arduino but none with the same phylosphy. If you know one, please let me know. Regards,

Topic by BaptisteL8   |  last reply


9v to (5v-3v) for pic 16f628a

Problem: I have a 16f627/628 (runs between 3 and 5 volts) that needs to work in tandem with another device (call it D) running at 9, direct current, (active for 1 second in 30 or less frequent). Upon hooking up a number (of descending in size) resistors (without D connected) with the supply and 16f6xx the 6 LED's powered by the 16f6xx do not turn on unless resistance is extremely minimal, and voltage is well above that advised in the datasheet (not to mention making the pic reset itself every 10ms). Can anyone tell me how I might run the 16f6xx from a 9 volt battery, and explain what was going on? This may seem unforgivably dim to anyone who knows but unfortunately I'm more a software guy learning hardware as I go along. Any help would be much appreciated, Thanks Andy

Topic by andy   |  last reply


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?  

Question by supertechey   |  last reply


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!!!

Question by jbdawinna   |  last reply


WHICH IS INPUT AND OUTPUT OF THIS? Answered

Tbd392nr lcd inverter

Question by yhdesai   |  last reply


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.

Question by GenAap   |  last reply


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

Question by Morgantao   |  last reply


What t is the difference between the -12v and +12v, -5v and +5v...in a computer power supply? Answered

 I am building an AC to DC power supply based on several Ibles and I am not sure I understand what the 2 different voltages are (-12v, +12v; -5v, +5v ....) Thank You!

Question by missplumeau   |  last reply


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= http://www.abstractavr.com/products/dmx-led-drivers/60w-dmx-led-driver/ Led Strips= http://www.adafruit.com/products/306 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.

Question by Pathogenex   |  last reply


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).

Question by akki5230   |  last reply


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.

Question by zack247   |  last reply


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.

Topic by RaptorHunter   |  last reply


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?

Question by Shiron   |  last reply


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).

Question by Shadow Of Intent   |  last reply


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 :)

Question by junits15   |  last reply


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

Question by ismael01   |  last reply