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5 Volt Regulator question (7805).

My students are building a shake cell phone charger and I know there's going to be a lot of current (hopefully) and voltage making it's way to the 7805.  I don't want anything to be lost as heat, so does the 5 volt regulator need a heat sink??  Thank you so much!!!

Question by mckywer    |  last reply

Question about a 5 Volt boost regulator?

Is there a cheaper version for the NCP1402 5V boost regulator? One of those is $5.95! Any help would be appreciated!?  Thank you! Patti

Question by mckywer    |  last reply

5 volts ballast

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

Topic by remyjovero    |  last reply

3 volt voltage regulators?

Hi,I need a 3 volt voltage regulator,1 ampere(or lower).I tried looking for Lm 7803 but couldn't find it any local shops.Anyother alternatives?

Question by Adarsh_tronix    |  last reply

Regulator Help

I am currently building an LED panel, and need some help setting up the regulators. I am using LM1084-ADJ regulators. What I was wondering is if anyone can tell me how to regulate the current, as in the math I need to calculate what resistance value I have to put between the adjustable, and Vout pins. The guy I was using simply stopped replying.

Topic by MaXoR  

Portable 3.3v regulator for a 9 volt battery? Answered

I've seen a great deal of portable breadboard PSU's that output 5 volts from a 9 volt battery, and I find these fantastic! However, I was there any way to refine this futher down to get a steady 3.3 volts? I would like it to be something close to the system that sath02 has made here as it not only better suites my nees, but makes sense to me. Thanks in advance!

Question by DoctorWoo    |  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

16 volts and a LM7805? Answered

I was wondering I'm making a very tiny project with that requires 5v. I'm using these little 3v batteries (CR2016). If I use like 6 of those and a 5v regulator, approximately how fast will they drain? Is that not a good way to lower the voltage? 

Question by HavocRC    |  last reply

voltage regulators and supercaps? Answered

I have 12 .22F 5 volt supercapacitors that i bought recently. Ive been thinking about making something like the Mintyboost from Adafruit but am unsure on how to do it with supercaps. Any help is appreciated as this is stumping me pretty well. thanks, bud

Question by budhaztm    |  last reply

How do you test a dc voltage regulator?

I have a dc volt regulator that reduces the voltage to around 12 volts. How can I tell if it is good or not?

Question by DELETED_afw11    |  last reply

12vdc to to convert ? Answered

I have one supply unit at 12 volts and i want to get 5 volts also. i need resistance or voltage regulator like lm317?

Question by napoleonis    |  last reply

How to increase an output of 5 volts to 9 volts?

I have a fixed input and the output is 5 volts. What type of design must I create to increase my output voltage to 9 volts with the already given output of 5 volts? I am trying to make this charger project as small in size as possible. Any assistance with this would be great. Thank you all!

Question by fr3dd4    |  last reply

120 volt ac to 5 volt dc circuit?

How to build the circuit that is in those devices that plug into 120 volt receptacle and can have a usb charger cable plugged into it. I just need the circuit diagram. I am a little familiar with schematic reading. It all fits in that little plug in device, so it can't be that much, right?. Thanks.

Question by stevecinstrfme    |  last reply

Small Voltage Regulator

I am looking to buy or build a small voltage regulator that can fit in an O gauge electric train engine. It needs to have a 18-20 volt AC input and 10-12 Volt AC 1 amp output. I would like to buy one already built, buy a schematic or a schematic with the parts to build. Thank You

Topic by frankv6    |  last reply

How to build a 12 volt to 1.5, Volt DC/DC Converter

Greetings all.  I suspect this is a pretty remedial question but I've not been able to find help or instructions here I am.  Basically I want to build my own 12V to 1.5V converter to power a small electronic device in may car that is currently chewing through a lot of batteries.  Such converters are cheaply available online but what would the fun of buying one be, if I could make my own instead?!  Can anyone help me get started by pointing me to an online resource with information on how to make such a device? Many thanks

Topic by mcbenney    |  last reply

How can I raise 1 volt to 5 volts?

I have a TLC module that i can get to produce about 1 volt from my hand.  I would like a way to turn this into 5 or more volts.  Any help would be greatly appreciated.  Thanks in advance.

Question by pianoman99a    |  last reply

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!

Topic by HavocRC    |  last reply

LM7805 voltage regulator output 4 volts?

I have a LM7805 voltage regulator hooked up to a saltwater battery that outputs 16 volts, and the output is either slightly above or below 4. When I wire it to a 9v battery, it outputs a steady 4.98, but still will not power a USB port

Question by D5quar3    |  last reply

12 volt stabilizer/regulator (high current)

Hi, I need something that's able to regulate the car voltage that vary from 10.2 to 14.7 (with lower voltages at startup that's not relevant)  to a stable 12v with a tolerance of 1-2% at high current (need at least 35A but I don't want to full load it too often then 40A would be better). I saw something like a lm317 with some external transistor that's able to put out something like 15A but it required a 30V input and it was a too much low current. can you link me an image of a circuit that's able to do what I want?

Topic by andry08    |  last reply

Help with Voltage Regulator

Hi, I have put one of these together for an ATX power supply and have come across something that I might be getting wrong.... In mocking up the LM317 circuit in breadboard (standar one found everywhere on line and on the LM317 pages), I have got the thing metering -11v to +11v??? I am using one of the black ground wires of the PSU on the black side of the volt meter, but cant figure out why I am not just getting positive voltages??? Could the diode be faulty? Or is this in fact correct? Any help appreciated...

Topic by lone_viper    |  last reply

Need a 100v voltage regulator?

So what I am trying to do is make a variable power supply from a computer PSU, I've done thise before minus the variable part. I need a voltage regulator that will limit 200 or more volts to 100 volts DC. I also need different variable voltage regulator that will allow me to adjust this from 0 to 100 volts, they usually have a circuit in the datasheet that uses some resistors and a potentiometer. So, are there voltage regulators like this? If not what is another way to do it?

Question by XOIIO    |  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 9 volts to 6 volts? Answered

I have a small r/c tank that is 6 volts  .the problem with it is it is made to take CR123A 3 volt camera batteries  .which run about 5-7 dollars each  .i could by rechargeable ones for 50 but i thought it would be easier and more cost effective to convert it to run on a nine volt rather then four AA or AAA  .not just do to the cost but also because the space limitations i know how to solder and built circuits if i have a schematic provided .so could anyone provide me with a small circuit schematic or is it just in need or putting a resistor in between the terminals?

Question by somebullcrap    |  last reply

3 volt signal to trigger 7 volt? Answered

Ok,so I get a 3 volt signal from a detector and use this 3 volt to trigger an alarm which atleast need a decent 7 volts to function.The detector could take a max. of 5 volts input which I got from the 7 volts DC supply.This 5 volts fed,gets transformed into 3 volts after the detection.So let me make this clear,I have a 3 volt and a 7 volt supply.I need to use this 3 volt to trigger the 7 volt circuit.I know what you are thinking-a relay !right?but I couldn't get  a 3 volt relay anywhere(though I got a 5 volt relay).I can tackle this situation in two ways.1)Either by stepping this 3 volt to 5 volts and making the relay do the job.but how? 2)Or some circuit to use this 3 volt to trigger the 7 volts(like a relay but maybe by using ic's).This is the final part of my project and so please help me.

Question by Adarsh_tronix    |  last reply

can you u get 12 volts down to 3 volts by using a 5 volt regulator and a 1/4th wat resistor? Answered

I need my car to go from 12 volts to 3 volts for LEDs... please help me!

Question by led235    |  last reply

How to configure LM317T to deliver 5 amps?

Hi guys, I'm new to the site. I wonder if someone could help me resolve my problem. Well, I'm trying to build a Laptop AC Adapter, but I can't get these components right now: -A Transformer -A voltage regulator other than LM317T and I have no experience with other ICs. So I'm using a DC to DC converter. The input power supply is a Z12 Lexmark printer AC adapter. It gives a DC output current of 830mA under 30 volts (actually it's 37.5 volts, I've checked this with my multimeter). However, the output I would like to get is 4-5 amps under 19.5 volts. I would like to mention that I've already given it a try. But the output current I've got wasn't enough to feed the laptop. I've used an LM317T and adjusted the voltage with a 6.6k resistor and a 47k potentiometer down to 19.5 volts. If there is a way to boost up the current with a joulethief or using a set of transistors or parallels LM317Ts, please tell me. Also, I hope that you give me the part number of all the components to match up with the LM317T because I must use this type of regulator. Thanks for your help and please consider my situation.

Question by junkrecycler    |  last reply

How to get 12 volts from 18 volts

How would i regulate 18 volts(2 9v batteries) to put out 12 volts instead? im doing this because 2 6v batteries is really heavy(im replacing 2 6v batteries, and they are also broken... dont ask how) thanks

Topic by ledzep567    |  last reply

How can I use a 6 Volt power source to power a 5 Volt USB port and a 1 Volt LED? Answered

How can I use a 6 Volt power source to power a 5 Volt USB port and a 1 Volt LED?  I know I need a regulated voltage for USB, but how can I get the remaining power to go to the LED?

Question by Validis    |  last reply

how do i use a 7805 voltage regulator with 6 volts power supply? Answered

How do i use a 7805 voltage regulator with a 6 volts power supply?

Question by imakethings    |  last reply

How to make a 1-1.5 volt voltage regulator at 15 amps?

Hi, I want to make a high current (15 or 16 amp) voltage regulator that outputs around 1 to 1.5 volts. Does anyone know how this could be done cheaply and easily? I've looked at the 15 amp schematic in the LM338 datasheet (  page 11), which uses 3 LM338s in parallel, but I'm pretty sure that takes the minimum output voltage to about 4v, way too much for me. I've looked at using 2n3055 transistor, but it seems like I'd need ridiculous heatsinking and probably fans to avoid thermalling out. I'm thinking of taking my power from an old PSU, 5 v rails, so not too much of a voltage drop, but it's hard to find stuff that can handle these kind of currents. I'm pretty much stumped right now, anyone got any ideas?

Topic by lolkent    |  last reply

Will a switching regulator charge an Ipod? Answered

I have a 16 gb Ipod Touch and I wanted to be able to charge it from an old laptop battery that is 14 volts. I did not like the idea of using a 7805 because it is so wasteful, so I was thinking of using a switching regulator like this one because it has an efficiency of 85% @ 14 volts.;=LM2591HVT-5.0-ND Something in me is just worried that because its switching on and off really fast to achieve the voltage that it will not work for charging my Ipod, so I came here to ask "will it work and is it the best option?"

Question by flybye22    |  last reply

Battery charger regulator question?

I've got a 40 amp 12 volt  RV power supply that I want turn into a battery charger.  Anyone got any ideas about how to regulate the current so it doesn't cook the batteries?? Thanks 

Question by jimnjo    |  last reply

How to set voltage on LM317 adjustable voltage regulator? Answered

How do you set the voltage regulation on an LM317 to 5 volts?

Question by Xixfas    |  last reply

How do I raise 3.7 volts to about 5-6 volts?

I have a battery that has an output of 3.7 volts, but that's too little for the project I'm doing. I need about 5-6 volts that I can work with. I'm driving 6 arrays of 2 leds, powered by an IC that I've programmed (for what its worth). I was wondering if there was an amplifier circuit, a step up circuit, a transistor, dc-dc converter, a surface mount Genie I can use to boost the power of my battery. Community, I call for your aid!

Question by Prestond    |  last reply

How to make Voltage regulators

I would like to know how to make a voltage regulator for an old generator. The regulator has stopped working and is hard to replace. I need an out´put of 120 volts with 15000 watts and ofcourse the 50-60 hertz. Thanx for your time

Question by Soochi    |  last reply

Trying to change 120 volt AC to 120 volt DC.

I have the full wave rectifier rated at 400 volts and 8 amps and need to know what kind of capacitor/ voltage regulator I might need to accomplish this. I'm powering two 100 watt lights off this. Thanks!

Question by evilgenius32    |  last reply

How should I regulate the power for my motors?

Hello, I am planning on building a stepper motor driver using Tom McWire's design. I want to control 3 motors which are rated for 7 volts, 350mA, and 20 ohms. I plan on using a 12 volt 5amp power supply. I am trying to figure out what kind of resistor I should use so that I do not fry my motors. Maybe I am missing something, but this is the way I am looking at it.... If the motor is using 7 volts and the power supply is 12 volts, that means i have 5 volts left to use. 5v over .35amps (the amount the motor uses) is 15ohms. (14.28 rounded up) That also means it uses 1.75 watts (5*.35). Would a 15ohm 2 Watt resistor be sufficient or am I looking at this all wrong? Thank you for your help in advance, folks :-D

Topic by TheLostAmish    |  last reply

**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

Topic by littlechef37    |  last reply

Need regulator and compact solenoid 5/2 valve for small scale Co2 powered system.

Looking to drive a 5/16ths inch pneumatic cylinder all in a self contained package. Cylinder is rated for 150 psi and the 12 gram co2 i was planning to use is 900 psi so i need to reduce it considerably. I'm trying to make a moving costume piece, not a battlebots weapon or a bomb.

Question by Chirishman    |  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

Can my walky-talkie take 5 volts? Answered

I have a set of walky-talkies, and they have horrible battery life, so I was planing to use them as intercoms, one getting power from my usb port, one getting power from an mutilated cellphone charger (both 5 volts). my Walky-talkies are meant to use 3 AAA batteries. (4.5 volts). is this setup possible, or will it ruin my walky-talkies?

Question by leggomylegoeggo    |  last reply

12 Volt 5 Watt Solar Panels- $19.99

UL Solar has 12 volt 5 watt solar panels for $19.99. I bought a couple of these about 2 years ago. The price has not been this low since then. Luxstar is not affiliated with UL Solar.

Topic by luxstar    |  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

What resistor do I need to drop 9 volts to 4.5 or 5?

I need to use a resistor (not a voltage regulator, sorry) to drop 9 volts from a battery down to 4.5 or 5. I am running an attiny85, which is also used to power up to 3 30ma leds. What do I need to use?

Question by XOIIO    |  last reply

will putting five volt regulators in parallel reduce the strain on them?

I'm using a peltier plate and some CPU fans to make a micro fridge for my car. for testing purposes, I'm going to need a pretty beefy power supply. because the plate draws four watts at twelve volts, I need a supply that can push out around three and a half to four amps. however, I don't want to go out and buy something, because I have a very limited amount of money. what I do have, however, is a large amount of leftover twelve volt regulators from an earlier project, rated to work with up to one amp. will connecting several of these in parallel (maybe five of them, just to be sure) be enough to reduce a thirteen and a half volt power supply with 3.9 amps of current to twelve volts? this is the closest I can get to a twelve volt supply with the materials I have, and I already have a heatsink for the regulators (I tore apart a dead computer power supply).

Question by codongolev    |  last reply

How do I set the lm317 voltage regulator to only output 1.2v? Answered

I have a 1.2v regulator (lm317) and I have a circuit that is producing about 3v. How do I connect the two together so that I have a 1.2v output?

Question by fullcircle    |  last reply

48 volt power supply

Hello everyone. i am interested in building a power supply from 0-48 volts and able to push a good amount of amps. any one have a ruff idea on how to beable to adjust the voltage and not limit my current to 2 amps i would like to puch say 15-20 amps. i can build the rectifier i have a 600v i think 30 amp bridge rectifier. just not sure on how to do the adjusting without useing a regulator chip that only pushes a few amps. any help would be greatly appreciated.

Topic by omnacron    |  last reply

Laser Driver with Limited Parts?

I have been working on a laser engraver for some time now, and have just recently gotten the laser parts.  I need to make a laser power supply, which I currently have a 5-volt fixed regulator which turns 15v 380ma into (obviously) 5v with roughly 400ma (value on label is not completely accurate).  I know that diodes will drop ~.6-volts, which I have a line of about 7 of them for testing, giving me 2-volts with the same current.  The problem I'm having is, I put proper resistors into the circuit to give 200ma to the diode, but every time I attach the laser to test the current it always reads 17ma on my volt meter.  Why is this?  How am I able to build a proper laser driver with limited parts (limited to a large supply of resistors and mixed caps, no adjustable regulator)?

Question by Frowney001    |  last reply

Volt conversion with mobile charger ?

Hi, I have to DC device  a) works with 5.V    (b) 1.5 Volt...  I am using mobile charger as a power supply.  How can i connect them with one mobile the charger output is 5.V  only.  a) works fine but as the other device require 1.5 Volts . Which type of power  component should i use to supply additional appox. 1.5 Volts ? will any of these can device blast ? Any type of tips n tricks will be very help full. Thanks, Richi

Topic by RichiV    |  last reply

Linking 5 battery powered LED arrays?

Let me preface by saying I can do a lot of things myself but have no training in electronics.  If someone can give me a diagram and values for the components I can construct it. I have 5 LED lights which each run off of 3 AAA batteries (3.6 volts).  I would like to take the LED arrays out of all of these and make them into one big light that I could run off the 18 volt batteries from my power tools.  Can I just wire all the lights in series or would I need some regulator circuit to prevent them from burning out?

Question by etcmn    |  last reply