9v to 3v

Hey, I need to know how to turn 9v into 3v can anyone help? Thanks, Cory

Topic by Flumesoft   |  last reply


9v shocker

Hey everybody. First, take a look at this question's best answer - https://www.instructables.com/answers/How-can-I-make-a-9-volt-shocker/ It tells you how to make a 9v shocker out of a CRT monitor's flyback transformer. I really like the idea and I just have an extra monitor at my friend's house, so I thought about trying it. I saw some videos of people messing around with flyback transformers, and it really looks dangerous. If I follow the guide on the link, and get the shocker to work, will it be dangerous? I'm gonna use it for pranks and self defense(I'm a HUGE fan of knives and I know how to use them, but they're illegal to carry here and can cause serious injury), will it be ok? Thanks a lot, Mike.

Question by netbus   |  last reply


9v VS 9vdc?

I'm working on an LED IR Illumination circuit (KipKay's nightvision with just the LED circuit). The thing works great but kills my 9v batteries pretty quick. I have a 9.6Vdc 300ma power adapter. Is is possible and SAFE to use this in the circuit instead of a 9v battery? Sources: KipKay's Project https://www.instructables.com/id/Super-Nightvision-Headset-Hack/ Power Adapter http://www.noiseguide.com/product_info/h_pro_96vdc300ma_adapter_ps200r120  

Question by mrgrim333   |  last reply


Led powered by 9v

Hi all. I am new to this forum and need some help. I want to mount an led strip to the bottom of a roller skate. Everything I find already made up requires 12v. I need to keep the setup as small as possible for mounting reasons. How could I go about making a 12vdc led circuit work off a 9v battery or how could I wire up some led's on a flexible strip powered by a battery. I am thinking 9v because I can purchase a rechargeable set without draining the bank account each time. Any suggestions are welcomed. I have about 6" in length to mount the strip to. I would like multi color led but one solid color would also be fine. Thanks again for any suggestions.

Topic by rsfaze   |  last reply


9v battery simulation?

I want to use a lab power supply to run simple ohm's law experiments instead of using a 9v alkaline battery. One of the experiments uses a resister in series with an LED to show the effects of how a resister limits current. I can set my lab power supply to 9V but I don't know what current to set it to in order to be the equivalent of the 9V battery. Can anybody enlighten me please? I'm just getting into learning electronics.

Question by woodyd   |  last reply


18v dropped to 12v?

I want to limit two 9V battieries, in serial to 12v. I want to run a cold cathode off em, if the strain is too much, I'll join two parralell sets of two 9v batteries in the circuit. Anyway, how do I do it? I can't find any 12V regulators at all, and I don't know what sort of resistor I'd need, is there one that would limit it to 12V, with the standard 9V battery ampage? How could I archive this? Thanks.

Topic by Josho   |  last reply


Does anyone know how to convert 9vdc power to 12v dc power?

Does anyone know how to convert 9vdc power to 12v dc power? ive looked all over the internet and nobody seems to have any schematics for anything like it. It needs to be about one or two square inches. Its for a pellet rifle with a built in air compressor so i can travel through the woods and not have to worry about going back to the truck and airing it up. please email me at mongoose_08@yahoo.com thanks

Question by mongoose_08 


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


Solar 9V battery charger? Answered

I was wondering if you could make a solar 9V battery charger and if you can you show me how?

Question by sf49ers   |  last reply


Powering an Arduino with 9V batteries? Answered

I'm looking at powering my Arduino with 2 9V batteries wired in parallel (2 is optional, but if you think a single 9V battery can power an arduino + 16 LEDs simultaneously for >3 hours, let me know). I have a few different options for linear regulators. LM350 (3A), C33275 (300mA), LM7805 (1A, 5V) - I'm guessing I should use the LM7805 because it's fixed at 5 but I'm not sure. I'm not too electronics-savvy so as much help as you're patient enough to give would really be appreciated!

Question by jonrb   |  last reply


Make a 9V powered zapper? Answered

My friend has this thing that looks like a pack of gum and when you grab and pull the piece sticking out it shocks you, it isn't really that powerful, but I want to make a better one.  I opened it up and it is a fairly simple device.  It has three button cell batteries with the negative side attached to a contact plate and the positive attached to the capacitor.  The capacitor has the neg attached to the same plate as the batteries negative.  The only problem is that the positive plate is attached to a third prong on the capacitor.  Why would a capacitor have three?  I have tried charging a 220 uf cap. with a 9v battery, but it doesn't deliver any shock even though it should be higher voltage and capacitance than the original device. 

Question by jj.inc   |  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


im new. questions about led and a 9v.

Circuit boardim trying to create a circuit board with leds on it that spells out my handle. i was thinking of using it as a throwie or like a calling card. im totally new to this so i didnt want to try and use a printed circuit board since i have never done anything like this before. i used a circuit board i bought at radio shack. im building it with standard super bright 5mm leds that are about 2.1 v and im not sure how many Ma. i assume 25 Ma. no matter how i plug these numbers into my formula (source volts - led volts / Ma) the leds always seem to run hot. i cant figure out what resistor to use. the power supply is a 9v battery. i also would like to know how to string about 30 of them together off one 9v. i know its alot but can anyone give me some advice or help me out?

Topic by mat_massacre   |  last reply


How long can a 9v battery power a few leds?

Hi I am trying to make a display of my polymer clay angry birds in our local fair and I wanted to add a few little leds on it, the problem is they need to stay on constantly for at least 5 days  I am trying to figure out how long a 9v battery would power about 6-8 leds. is there a better way to do it? ~Thanks  

Question by AsherB4   |  last reply


Can a ring illuminated 5A 250VAC pilot lamp (6v led lighted switch) control a mini pc fan using a 9v battery ?

The fan is for the combustion chamber of a spud gun and comes with an internal toggle switch but I would like to use the external lighted switch. Suggestions are appreciated, Thanks

Question by JackH19   |  last reply


Where can i find prints to a voltage multiplier for 9or 12 v?

I need to build a voltage multiplier for 9v to about 4kv

Question by tulavatalo   |  last reply


Rocket Ignition Switch?

I have seen multiple high power rocket igniters, but none show you how to wire them.  I want to link three 9v batteries in a way that outputs 27v.  How do I do that.  Is the wiring (+|-|+|-|+|-) or (+|+|+|-|-|-)

Question by jj.inc   |  last reply


Is it safe to power a 9v=150mA (cordless phone) with a 9v 300mA adapter? Answered

I have a Philips CD250DUO cordless phone that has no user's guide , and a GE Atlinks cordless phone that is powered by 9v i50mA i wonder if i could use my 9v 300mA adapter on the Philips brand and can anybody tell me if there is free download of user's guide for this device

Question by jovenhatsjr   |  last reply



Multi- 9v or 12v outlet setup?

Does anyone know how to make or where to find a single wallwort (120v outlet) that has multiple 9v or 12 v out plugs? I've got alot of little electronics (mainly things that light up/ glow) and I hate all the blocks and power strips that I've got to use. (I'm in the US btw.) Thanks for any help! The Atomic Soul

Topic by TheAtomicSoul   |  last reply


how many ohm resistor do i need to get 5v from a 9v battery? Answered

Hello i am writing up an instructable on setting up a wireless receiver , however i requires both 5v and 9v output, and the whole point of it is that it is simple and cheap, so i need to know, how many ohm resistor do i need to step down 9v down to 5v? i do not wish to use a 5v regulator unless one can be bought for less than $2, or else the instructable will cost too much.

Question by oldmanbeefjerky   |  last reply


Can anyone please calculate the color code for a 9v DC Resistor. Its the last thing I need to finish my whole project.?

I'm trying to light up the dash in my truck and everything is ready except im plugging it in to the 12v DC cigarette lighter and I know it will blow them all sky high but I already tested and 9v DC is what I need. Thanks in advance!!! 

Question by TamaMan14   |  last reply


Wiring help!

I have an 8th grade science class (I'm the teacher) that I would like to have construct underwater vehicles.  The kids will be using 9v batteries, switches and assorted other materials.  Does anyone know of any good books/articles that explain the basics of wiring, electricity, motors, switches, etc.  that I can have the students read to get a good base of knowledge in the basics of electronics? Thanks!!!

Topic by mashmtz   |  last reply


How can I make a spark gap powered by a 9 volt battery?

I had an idea for a project where I will (literally) Set Fire To The Rain. So I need a spark gap. Anyone know how to do this? I think it would be easy to charge, then discharge a flash capacitor. If that's a good plan, where can I find a schematic for a charging circuit?

Question by 4lifenerdfighter   |  last reply


How to charge a rechargeable 9v battery?

Hi guys, I am using a lot 9v volt batteries so I thought why don't I buy rechargeable but I found out that the charges where expensive. so does anyone know a circuit to make a charger?

Question by bobbiy   |  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


Wiring two 9v devices to batteries...

I want to run a motor attached to a motion sensor in such a manner that the motion sensor triggers the motor. The motor is run by 6 1.5v D cell batteries, thus I imagine requires a 9v draw. The battery operated motion sensor also requires 9v. If I wire them in series, which I (hopefully correctly) understand would require 18v total and thus would require some number of batteries wired in series to achieve that total. Correct?

Question by    |  last reply


Solar charger in altoids tin for 9v??

Well, if you have seen the altoids solar battery charger, and the altoids 9v usb charger, then you must have thought, "why not put em together???". Now, Im not electronics buff, but I'd be willing to bet that since the 9v charger instructable is so small, that it could be incorperated with the solar panel kit. Now, my question is, would i have to do anything ridiculous to convert the solar charger (which is ment to charge 2 AA batterys) into a 9v usb charger w/solar panel while still being inside an altoids tin. PS: I still don't know why I have this wierd fascination with altoids tin DIYs, but I do...

Topic by altoidsrox 


9v controlling 2 servo motor?

Hi everyone! i am planning to use 2 servo motor and a LCD, all connected to my arduino. but of course, the 5v from the arduino aren't enough to power up everything. so my question is; can i use an external source (9v battery) to power up the motors? if yes,  how? appreciate the help. thanks. 

Question by nurazureen   |  last reply


9v to 3v "easy button" hack. Answered

Hello! Im working on a Staples Button Hack! but..... Problem that I have is that I feel like it is a Waste to scrap the original "that was easy" message. And the problem that comes along with this would be that I have to use a 9v battery to power the new circuit and the original button circuit uses a 3v battery. I'm not great with Ohms law but I do relize that I need a resistor but... i do not know if that will put in too much current into the original circuit?Would anyone know how I can calculate this? And does the amount of current even matter? -Thanks! Noobiefied

Question by noobiefied   |  last reply


Help with wiring a 9v screen to 12v

If you are interested in what i am doing with my wii check it out ( http://www.wiinode.com/forums/index.php?showtopic=4280 ?... ) As you can see with my site i have a screen that uses 9v and i need it to be used along with the wii (so i only have to carry around ONE plug in) i have my amp wired to my wii using 5v and it works great. I need my screen to work alongside my wii. Ive tryed a 9volt battery before but some reason i get a blank screen but my ps1 7v power connector makes it light up good.when i plug 5v on the screen it leaves it very dim. There is 12v also there are alot of 5v points and some 3.3v points on the wii, could i combine them in some way to recieve my needed voltage or use the 12v? anything thats not to costly or spacey (need my smallage so i can have a small case) and please dont post about me NOT needed to do this thank you. if you need more info say so and ill update the question. I KNOW THE RISK INVOLED WITH WHAT IM DOING!please also note that pics are old. Just giving them for info purposes. Please ask me if you need any other details. :) thank youEDIT: fixed the link.

Topic by Wiimote Master   |  last reply


How many amps do i need to power two LED Cob 9v bars ? Answered

I was wondering how many amps would these two LED bars need in order to work if connected in series, and would a regular 9V battery be enough to power them ? http://www.dx.com/p/high-power-3w-7000k-200lm-white-led-puri-chip-emitter-metal-strip-12-14v-65783#.VgrNC9RXeK1 What kind of battery should i use if a 9v isnt enough ?

Question by TarikS5   |  last reply


can a 9v be used to heat a piece of wire without the danger of blowing up? Answered

I am working on a costume that utilizes shape memory metal. I plan to use a 9v to briefly heat the metal to its transformation point of roughly 115F where it springs to shape but I would like to prevent any possibility of this momentary short circuit from blowing out the battery. I have yet to fully grasp the applications of diodes, transistors and resistors. is there any kind of simple setup someone may suggest? I've also considered the use of microcontrollers or relays but im trying to keep as simple as I can.

Question by SideTracked350   |  last reply


What sort of resistor will i need for 8 IR LEDs wired in series and powered by a 9v battery?

I plan on wiring 8 IR LEDs in series with a 9v battery to power them. i pulled the LEDs out of some remote controlled helicopters so I'm not sure of the values. if there's a safe way to go, what resistor/s should i use?

Question by tokymaru   |  last reply


my 9v batter is overheating on the LEDs (This was a DIY project I'm worried I messed up somewhere)?

Hello guys, I'm pretty new to LED work and this might seem like a really round about process to how I did this but I'm going to explain the whole thing and hopefully find a solution to my problem! First off I bought these Fairy Lights:  https://www.amazon.com/gp/product/B01MD1RQ6Q/ref=oh_aui_detailpage_o01_s01?ie=UTF8&psc;=1 I bought them to put into rave fluffies (that I hope to sell at some point) I've attached photos below of what they look like if people didn't know. I bought them because of the small battery pack so they could sit nicely along the legs and not bother anyone and, because they're rainbow and do a beautiful blinking pattern. The problem with them is that the battery packs completely sucked. Big time. They would work for about a minute and then start loosing higher voltage colors and then about at the 3 minute mark they would just be totally red. I figured they were crappy batter packs so I decided to mess with it. Rave Fluffies: http://ep.yimg.com/ay/yhst-11088499841243/striped-fluffies-monster-blue-pink-purple-white-24.jpg The fairy lights themselves were to short so, I decided to solder to strands together, then I trashed the battery pack that came with them and replaced it with a 9v batter pack adapter. I tested it out on some 9 volt batteries laying around the house and it looked magical. All of the colors stayed much longer and it was beautiful!  So, today I went out and bought some new batteries they're Energizer Max 9V. I put the fluffies on and put them in and I wanted to test how long they would last. By about 5 minutes I felt a burning against my leg where the battery was. I took the fluffies off fast and discounted the battery. It was extremely hot. Almost to hot to touch and it left two nice low key red burns on my legs. I don't understand what caused this when the other batteries were fine? I also used a 9V energizer battery before. But, the only difference is I'm not sure how much power was left in it while these were fully powered! I hoping to find a solution to this and hopefully it's an easy fix! Also, Bonus points to whoever can send me in the right direction to buy fairy lights like these. Rainbow, blinking, with a small battery pack that doesn't poop out on me fast. I would prefer not to do this much work or something I intend to sell but, if that's what has to happen it's not the end of the world. Thank you so much!! Much love,  Meisha 

Question by MeganB126   |  last reply


How should I do it? Answered

I want to make a small inverter with 10kv output powered from a 9v battery. Can you help me with a schematic?

Question by theVader75   |  last reply


Power the Arduino alone

Heys guys, Ive been using the arduino(without any shields) just playing around with LED's. I want too control my arduino without it being plugged in the computer via USB. So how would I do that. Should I use a battery pack or a 9V attached to the jack hole? thanks guys

Topic by vek11   |  last reply


Batteries and LED light modules - correctly powering for maximum life

Hiya, I need to power a LED strip of 3 LED lights with batteries. The LED box says it is a 12VDC light module, and on the back of the box it says the Input Power is 0.0453A. My limited understanding is that I should use a 9V battery plus 2x AA battery (I have limited space - a 8 AA pack wont fit inside my project)...is that correct? I need to know how long these batteries will last - if it is less than 10 hours can you suggest another way of powering it? I'm incredibly lost and very new to understanding all of this! Thanks in advance. 

Topic by SonyaS2   |  last reply


LM3914

So I looked up the data for the LM3914 followed the steps and I still cant get this thing to work I tried it two ways. I want to be able to set this up for variances of voltage say from 1.5V to 30 volts. Any advise would be great.

Topic by dominick.j.pezza   |  last reply


LED Voltage? Answered

So recently I had an idea to make a steam gun by heating steam with a NiChrome wire driven by a 9v battery, anyway, to keep it safe and so i knew when it was on, i decided to add an LED to the circuit. I went to http://www.hebeiltd.com.cn/?p=zz.led.resistor.calculator to see which resistor i needed. From what i understand, the resistor limits the CURRENT across the circuit. So, what i want to know is whether the Led will work with the first attached circuit and not bun out from the voltage, and whether the nichrome wire and led will work in circuit 2. EDIITTT: Well, after a few answers, i'm realising i cant run this off of a 9volt, so, what small powersupply could i use?

Question by LiquidLightning   |  last reply


LED Projects

For LED projects, click my profile name... reg ketan ----------------- "May the good belong to all the people in the world. May the rulers go by the path of justice. May the best of men and their source always prove to be a blessing. May all the world rejoice in happiness. May rain come in time and plentifulness be on Earth. May this world be free from suffering and the noble ones be free from fears" ---- Vedic blessing

Topic by pandyaketan 


How do you wire a small amount (8-12) LED's, to be run off a small battery and with a switch? In Laymens terms if pos?

Hi, I'm framing a piece of art with a deep frame and would like to put between 8 and 12 LED's in the frame. I will be running the wires and  hiding the battery and switch in a rebate around the outside of the frame. i will drill small holes in the frame every 2-3 inches through the frame for the LED's to be pushed into so they sit just below the surface on the inside of the frame. What i need to know is how to do it? From the basic knowledge i have i would have a 9v battery Positive wire into a switch,negative wire into 1st LED, then link all LED's with wire until the last negative wire into battery.  How wrong am I? I need to know how long the battery would last as well. Also needs to be wireless as it going to hanging on a wall. Thanks for any suggestions and help. And if anyone has a much better idea please let me know!!

Question by RyanW49 


DIY 9V DC to 110V AC inverter, and/or 9V DC to 19V DC transformer?

Hi, I want to build a 9V/110V DC/AC inverter, so I can power up things like my laptop with a car lighter socket. It would be always nice to be able to use electronics in the car when I'm traveling... What kind of components will I need and how would the schematic looks like? If DC/AC is a hard task, how would I go about building a 9V/19V DC/DC transformer so I can at least power up my laptop on the go?

Question by ddolbi1   |  last reply


12v device to switch on a 9v device (signal to switch on only)

I have a device that is switched on by a sensor, powered by 12v, 1.3amp battery. I have another device that is switched on by a mechanical push button switch, this is powered by a 9v battery. I want to piggy back on the wires that switch on the 12v device and take the signal (to turn on only) to the device that is already powered by a 9v battery and normally turned on by a push button switch. ( I want to replace this mechanical push button switch with an "electronic switch" turned on and off the the presence and absence of the 12v signal) I want the 9v device to switch on only when the 12v device switches on and switch off when the 12v device switches off. Also I want the 9v device to only run on the original 9v battery (not accepting power from the 12v device and not returning any power from the 9v device to the 12v device. Is there a switch device/relay that can do this? A device that I can just connect between the wires going from the 12v device to the 9v device? I am a novice to electronics please be kind. I an open to using part from another device, and basic mods. Thank you

Topic by Jvos   |  last reply


Can I use a 9v battery to power usb speakers?

I recently made a mini amplifier out of some usb speakers and at the moment it's powered by usb but I want to make it battery powered so do you think a 9v battery will be fine? I don't want to ruin the amp so I want to make sure but it has a 16v 470uf capacitor on it and that's about all I can tell you about the circuit board. I'd imagine it would be fine but is there any way to tell?

Question by jlandreth1   |  last reply


12V from 9V battery or other easy alternative?

Hello, I need a 12V 0.2A(min) power supply for a project... I don't want to use any kind of strange or expensive battery because it's a gift for someone. I was planning on using a 9 volt battery, is there any easy way to build maybe a step-up transformer for it (needs to be very compact)? Or could I use AA batteries? I don't want to use 8 AAs though, I do know that's be 12 volts... Thanks, any help is appreciated. 

Question by j.hawkins   |  last reply


How to hook up a solar panel to a 9v battery powered recording module?

I'm planning to make an outdoor thing that plays a sound so I want it to run off of a solar panel. I'm going to use a 9 volt radio shack recording module. I was just wondering what kind of solar panel I need, and how to hook it up. Plus if you know of a recording module that runs on a solar panel that would be great. Thanks a lot! :)

Question by ATOMIKMONKEY   |  last reply


Is my RGB LED broken, or am I just dumb? Answered

I have a 10W RGB LED like this one: http://dx.com/p/10w-1000lm-rgb-light-9-led-module-silver-white-9-11v-168507 It's rated to 9-11v, so I hooked it up to a 9v battery. The LED has 4 leads: 1) +9v 2) Red - 3) Green - 4) Blue - The green and the blue work as expected, and I can combine them to get cyan. The problem is with the red: 1) It won't combine with any other color.  If the red is switched on, the green and blue switch off. 2) It works on both polarities.... It turns on both with +9v and -9v. Am I doing something wrong?  Am I missing something?  Am I going crazy?  Am I just stupid!? Please help!

Question by Morgantao   |  last reply


Why does this work, and is it doing anything at all? Answered

Take a look at the pic, i have a 9v battery, two 50 volt 3300uF capacitors, and a 2.4 volt green 20ma led, when i hook up led normally i need a resistor and proper powr supply, but i was bored and started randomly hooking things together(mad science) any way i hooked the 2 capacitors together and wired a led inbetween them, plugged in the 9volt and the led started dim then got brighter then i have ever seen these crappy leds get, i left it on for 30 mins and it stayed on, i expected a fast burn out due to no resistor but no it was great, then i unplugged the 9v and the led slowly faded off which i kinda guessed would happen dimmed for 10 seconds then turned off.. ok my Q why did this happen, i have little expierence with capacitors, know they make good tazer but thats about it. and why did the led work like this with no resistor? is the capacitor pulling enough power that the 9v is working on lower volt? w/e answers please

Question by dougiedougworld   |  last reply