Voltage regulator?

I need to know how to build a 12v-5v pulse regulator for my fuel level sending unit/gauge in my truck. I would like to know what parts to buy and the order of everything. Thank you in advance. Daniel

Topic by gungfudan 6 years ago  |  last reply 6 years ago


Voltage regulation

I have a solar charge controller (Velleman SOL4UCN2) that outputs 12v, 6v and 3v. But I need 9v and I'm not sure how to get that.

Topic by pless84 10 years ago  |  last reply 10 years ago


Voltage regulator? Answered

Does a voltage regulator IC (e.g 7805, LM317 etc) still draw current when there is no load?

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


Voltage Regulator

EDIT: Anyone Interested please check below posts, this is one is obsoleteHello!I need a voltage smoother and regulator on my circuit(attached below)it is a modified shunt charge controller circuit.It converts the Tri phase alternating current to DC and feeds it into the circuit.The regulator will have to be attachable to the BATTERIES wire in the circuit.It should not consume more than 1v power on its own.My Vout to the battery currently is fluctuating.I will need the to be a stable 12v to charge the batteries. A potentiometer will have to adjust current.I will calibrate current according to my battery bank needs.Led 1 indicates 'charging' Led 2 indicates 'Dump'And Please forgive my circuit diagram design(it looks like crap)but works like gold.Also do NOT suggest huge changes to my controller for the regulator to work. Small suggestions to make it more effective,useful like change the zener diode power rating will be welcome.P.S- Its for my hydro project.Check it out at https://www.instructables.com/community/Help-Hydro-power/Kabir

Topic by mhkabir 9 years ago  |  last reply 9 years ago


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 3 years ago  |  last reply 3 years ago


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 7 years ago  |  last reply 7 years ago


Voltage regulator for laptop

Hi there. I have a problem for which I'd like some opinions: I have a PB laptop which has fried its inverter for the LCD due to the input voltage towards the inverter being too high (19v while it should be 12v and can only endure upto 13v). Most PB models have this problem. I looked around and some people suggest making a voltage regulator with a 7812 and some capacitors that gets its power directly from the input of the power adapter on the laptop (19v, 6+ amps). But since I am not really that into electronics, I have no idea if this will work, especially towards the heat that comes with the 7812, will it be high? The inverter needs around 0.5 amps input current. Others suggest a setup with (zener) diodes, but I have no clue how to start on that. Anybody have a suggestion? Many thanks.

Topic by .conne. 11 years ago


will this really regulate voltage?

Will this really regulate voltage?I would think that voltage could just flow arround the capshttp://electronics.howstuffworks.com/digital-electronics4.htm

Topic by kendallickes 10 years ago  |  last reply 10 years ago


Voltage Regulator Question? Answered

Hi Guys, Looking a bit into voltage regulators. When I'm looking at the wiring diagrams on the datasheets, most of them indicate that it requires a 30V+ish input voltage to work. I was hoping to get a small adjustable voltage regulator to run off the 12v range. I really don't need anything over 12volts anyway. Can I get this to work or do I have to find a power supply capable of providing 30V+ for the voltage regulator? I was looking at models such as the lm117 if it helps. Also, If I do need 30v+, where can you suggest I get that kind of power supply? I usually use 12v wall adapters. Thanks!

Question by transistorguy 7 years ago  |  last reply 7 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

Topic by mrshow555 11 years ago  |  last reply 11 years ago


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 6 years ago  |  last reply 6 years ago


Voltage Regulator circuit

I am trying to power Bluetooth module and the Arduino using a 9V battery. So tried to use a voltage regulator (KA7805) with 25volt 100miro farad and 63V 1 micro farad capacitors. I checked the circuit connecting these components using multimeter, it showed 5.06V as the output. But the problem comes when I connect the Bluetooth module to this output, which turns off after quickly. I checked the voltage at the bluetooth which is reducing quickly from 5V-2.5V in a matter of seconds and since the operating voltage of Bluetooth module HC-05 is 3.6V-7V, it turns off. I am not clear why this circuit behaving this way. Same output when I connected to the Arduino, it works seamlessly. Please let me know what are the mistakes that I need to rectify for this work. Thanks in advance

Topic by Bhanu Kishan 4 years ago


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 6 years ago  |  last reply 6 years ago


Voltage regulator for solar panel

I have built a solar panel as a fun little project, now it has come upon a big problem. The solar cells that I am using seem to have a higher amperage output and a lower voltage output in high intensity sun while having a high voltage and low amperage output in medium and low intensity sun. This poses a problem as my batteries were able to recharge during late winter and early spring but now are not able to recharge when there is the most energy to be captured during the summer. The average voltage during high intensity is about 11 while the voltage during medium or low is around 12.5 and 13. I want to know if there is a way to create a transformer to step up the voltage or create a voltage regulator that can withstand 13 amps so the battery can recharge properly. A link or any suggestions would help.

Topic by menace 9 years ago


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 6 years ago  |  last reply 3 years ago


Voltage regulator circuit design

Hi, I'm trying to make a DC - DC voltage converter. The real purpose is to power an old USB hub in a car. This is because so many of my electronics these days use USB to power them and rather than have a nasty mess of car power adapters I want to use a single 12V supply for the hub and then plug all of my goodies into it. Now for the meat of the question..... What is the best circuit design for using a voltage regulator. I have looked at some stuff in data-sheets and it just seems way too simple. The part I'm looking at using is a National Semiconductor LM1085-5.0. Input voltage 6.5 - 20V output 5V max of 3A

Topic by Sailing_Nut 10 years ago  |  last reply 10 years ago


Variable Voltage Regulators with + and - 12v input? Answered

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...

Question by lone_viper 7 years ago  |  last reply 7 years ago


voltage regulators vs resistors? Answered

What are the benefits of voltage regulators over resistors and vice versa? why to use voltage regulators if resistors can limit the voltage?

Question by Ahtasham Ahmad Mohtashim 5 years ago  |  last reply 3 years ago


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 7 months ago  |  last reply 7 months ago


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 9 years ago  |  last reply 9 years ago


6v 0.5a voltage regulator?

I need to drop down the voltage from 12v 1a to 6v 0.5a for a project but i dont know how to do this please help me !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Question by Andrew_48 8 years ago  |  last reply 6 years ago


Voltage regulator for trailer brakes

Im planning on building a motorized trailer dolly for my travel trailer, however i want to make a dead mans switch for the trailer brakes.  I was wondering if I took apart an old cordless drill if I could use the trigger as a voltage regulator to regulate the voltage to the trailer brake system.  Without getting into specifics of how it will connect to the regulator, I figure I would have like a bike brake handle that while applied the trailer brakes would be off, but if released that the trailer brakes would be applied incase the trailer started to roll away from you. Any suggestions other than "Go buy a trailer brake controller" would be appreciated! :)

Topic by Thunderbone 1 year ago  |  last reply 1 year ago


Voltage regulator Design Problem?

 Ah, voltage regulators. Easy Right! Not this one. I am making a voltage regulator like for an automobile regulator for a DC generator. (I'm replacing the old DC generator regulator on Pre 60's cars) A battery is charged from a winding on a Generator  (20V @ 60 Amps) A voltage sensor on the battery voltage turns on and off a switch driving the Field winding. The Field winding basically "turns on and off" the generator output. The battery is connected directly to the generator. (Why  and Why not is coming up) But when the Genrator's output is lower than the Battery voltage, current will flow back from the battery to the generator winding and discharge the Battery. So I need some isolation between the generator output and the battery. Alternators are easy since it has a bridge onthe output keeping the current from flowing backwards. Old regulators used a relay which burned out sooner or later. So easy, use a diode right? Just put a diode inseries with the generator to the batery. By the way, the "open circuit" voltage on a generator is about 200VDC No! The best diode I can find has a .7V drop at 60 Amps which is 42 Watts of heat to dissipate. Ahhh, so use a FET, They can get down into the milliOhms right? Except for the reverse polarity (and ESD) protecton diode always across the FETs defeat the purpose of a reverse polarity switch. So who out there is smarter than me? What goes inthe box marked ?? Any solutions accepted. Ungefahrt (now neither young or fast)

Question by ungefahrt 6 years ago  |  last reply 6 years ago


Problem in making a voltage regulator

Hi everyone! I have a dynamo on my bicycle which can generate AC 12v-30v during normal to fast cycling. I want to power electronics and charge batteries with the dynamo but do not know how to limit the voltage to around 12v DC. Any help would be greatly appreciated.

Topic by sirajmunir 11 years ago  |  last reply 7 years ago


Why do my lm317T and lm78XX regulators die so easily? Answered

While using my last 7808 voltage regulator as nothing more than a voltage reference for a breadboarded linear power supply design, I noticed that after a few small modifications, that the 7808 was no longer outputting 8V, and was instead floating 14.8V (kinda close to the +15V supply rail). At no point did the regulator overheat, and it was simply connected to the a 200K potentiometer to ground and a noninverting input of a LT1112. In the past, I have killed at least 3 LM317T regulators in my velleman 3-in-1 lab thingy, (it is a relatively simple circuit and was the first board I have ever fully reverse engineered.) The heatsink never did get too hot, but I used to always connect heavy loads to it that caused the overload lamp to come on. That LED was basically in series with a large resistor to the input of the LM317 so when the LED has enough bias voltage, it comes on when around 1A is being pulled. Anyways, I have killed countless other small 78xx regulators, one way or another, and even made some of them literally explode right away. (generally by getting the pinout wrong.) I blow up these regulators so commonly I even have video evidence lol! click to around 3:30 for the FAIL! https://www.youtube.com/watch?v=lPHHvVTVbwM So is it just me and my luck, or are these regulators which supposedly have all sorts of thermal protection, current limiting, and short circuit protection just not as rugged as they seem they should be?

Question by -max- 3 years ago  |  last reply 3 years ago


i have 12v 1A dc voltage supply from an adapter and 5v 0.25amp bldc motor so how to reduce voltage and power my motor?

Input 12v/1A dc power supply from AC to dc adapter ..  and want power a 5v .25 A brushless dc motor ... so want a stable and reliable dc voltage reducing circuit which will not burn out if used for long time.

Question by RajeshM64 2 years ago  |  last reply 2 years ago


Voltage Control: 20v DC

I am trying to find an electronic part that will take in anywhere between 12-36v and put out a consistent 20v. What could do this? And how can I get one? If amperage matters, I'll probably be putting between 1 and 4 amps through it.

Topic by V-Man737 10 years ago  |  last reply 10 years ago


is it possible to use a low voltage controller at higher voltage?

I want to make a isolated switching power supply intended to drop and convert 220VAC to 12VDC, but the only available controllers in my area can only handle 100VDC at maximum. is there a way where i can use those switching controllers at 220VAC?

Question by codestroy7 6 years ago  |  last reply 6 years ago


Where find 5v regulators?

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

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


DIY step up switching regulator?

I have a 6v power supply from 4 D cells that I need to convert into 24v in order to drive a solenoid. Can somebody direct me to a switching regulator circuit that I could build? Alternatively, if someone knows of a semiconductor that I could obtain that would do this, that would be great. However, I have looked around quite a bit and have not found anything. Again, my request is for a 6Vin to 24Vout switching regulator circuit, with about 500mA - 1A output... Thanks!

Question by raykholo 8 years ago  |  last reply 8 years ago


Zener Diode to regulate solar voltage

I'm new to electronics, and I'm having trouble with varying voltage. I'm running a 6V solar panel through a charge controller, and out to a lithium battery (3.7V) and a load (3.7V), in this case a GPS data logger. My issue is the varying voltage to the GPS. The GPS works perfectly off the battery (constantly diminishing voltage), but when the solar panel kicks in the voltage increases, the GPS thinks it is being charged, and switches off. The GPS will work on any voltage above 2.75V I was wondering if I put a 3V zener diode in series between the charge controller and the GPS, would this keep the voltage at a constant 3V even if the solar panel is producing the 5V needed to charge the lithium battery?  I hope this makes sense Thanks

Topic by blakea 5 years ago  |  last reply 5 years ago


ATX Variable power supply circuit problems? Answered

I finished putting together the variable power curcuit board I had asked about earlier. I am getting 0-18volts with no load applied just my meter. When I try to connect a small dc motor or anything to it , my voltage goes to 0. I used a 5k linear taper potentiometer and didn't notice untill after assembling that it is only rated for .5 watts. Could this be the problem? I also used a salvaged ceramic cap, and a salvaged 1uf cap, but dont know how to test them with a regular fluke multimeter. Could somebody please help! I'm a newbee, so I appologize for my electronics ignorance, but we all got to start somewhere.

Question by pollock9131 8 years ago  |  last reply 8 years ago


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 6 years ago  |  last reply 6 years ago


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 9 years ago  |  last reply 6 years ago


12v to 6v voltage regulator at about 15 amps

Hi, i have a 1963 VW bug that is very stock, but the 6v lights just dont work very well (dim at idle, then not too bright at speed) it is very simple to use a later 12v generator and then swap out all the lights, battery, coil and relays and it works great. BUT i have a 6v wiper motor and also a 6v gasoline heater that i will need to keep at 6v (the 12v parts are just not available or too expensive) I have found an article that recommends building a cheap voltage regulator using a 7806, ( 6 volt, 1 amp regulator) and 2 1uF 35v tantalum capacitors, then a NPN transistor which the original poster says is a 2N5881 npn transistor. here is the scematic. the pdf article is attached and the link to the original article is here http://www.studebaker-info.org/tech/6-12V/6-12-6.html  The questions i have 1. what is a 2n5881 been replaced as? i cannot find it at jameco and the original posted doesn't give any specs for it. 2. how would i "pump up" the amps available from 10 to anything else (looking for about 15 amps) thinking that the npn transistor is the key but i am new to this and wouldn't even begin to know where to look. 3. what happens if any item fails? can i put some sort of safety into this so it quits rather than passing any addition voltage through additional info the heater runs at about 85 watts so 85 watts / 6volts = 14.616 amps  the wipers run at much less than that so building 2 of this would work great.  Any ideas? Thanks in advance for any insight to this 

Topic by starvin 7 years ago  |  last reply 7 years ago



Varialbe current regulator?

Have you ever seen a variable current regulator? i googled it but i keep getting standard voltage regulators Any help would be appreciated!

Topic by Sandisk1duo 10 years ago  |  last reply 10 years ago


How do I tweak this voltage regulator? Answered

I pulled a power-board out of a 'phone charger (pic) The transformer and bridge rectifier have been removed and it's powered from a 9V motor. The charger says: Input 230V~ / 50Hz  / 40mA / 9.2VA Output 7V / 300mA / 2.1VA I'd like it to regulate to 5.0 V (for USB devices) - what do I fiddle-with? L

Question by lemonie 6 years ago  |  last reply 6 years ago


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 (http://www.ti.com/lit/ds/symlink/lm138.pdf  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 7 years ago  |  last reply 7 years ago


Voltage regulator or resistors to manage LEDs? Answered

I want to run a load of LEDs mounted onto a PCB. This is simple enough. I'd like to know what's best, using LEDs with resistors (with a little help from http://led.linear1.org/led.wiz) Or using a voltage converter (with a little help from http://www.reuk.co.uk/LM317-Voltage-Calculator.htm), and doing away with resistors Source voltage will be either 4.8 (4 NiMH AAs) or 12V (old wall transformers), LEDs will be white ones (3.3v)

Question by sladek 9 years ago  |  last reply 9 years ago


Pre set voltage regulator/supply

Hi I want to modify the DC to DC buck circuit that is sold anywhere, to have pre-set voltage by pressing only one button it will set at 3, 5,9 and 12 output

Question by nickp238 5 months ago


Voltage Sensor/ Regulator (with switching capability)

Hello All!! I am looking for help! I have a invention that deals with 12 VDC battery banks. I have a series of batteries that I would like to charge with a small solar panel. I need the solar panel current to be able to go from battery to battery as voltage levels drop below 12.55v and when they rise above 13.75v. I know this control-sensor-switch can be built. I just have no idea how to go about it. I also realize this site has some very smart people that use it and would appreciate any help. I am willing to give a $ reward to someone that can design this controller with a intructable video. Any takers?

Topic by starfishenergy 7 years ago  |  last reply 7 years ago


How do I Configure a Adjustable Voltage Regulator? Answered

Hello! Im working on a project that uses a 9v battery to power a circuit. I would also like to power a circuit with the same battery. But this circuit was designed to run off 2 AAA. I've gone searching and It seems like I was only needing a Voltage regulator to step down that 9v to 3v ish.  Problem is that I couldnt find a output 3v one! So I had to buy an adjustable one from Fry's Electronics. And I don't know how to configure this! haha, this is quite a problem. And documentation on this product is horrible. Can anyone please help me out?? Product is NTE1900 3 terminal positive adjustable voltage regulator. Input is 9v, I want an output of 3v. How would I set this up? Thanks!

Question by noobiefied 7 years ago  |  last reply 7 years ago


2 Voltage Regulators, 1 Power Source?

Is it possible to use two voltage regulators of different values with one power source?

Topic by flagrantfouler 9 years ago


How to regulate the voltage from USB solar panel ?

Hello, I got some USB solar panels. They output 3.5W at 6V each. I think the usb wire is directly wired to the panel without regulator and without diode like it should be. I would like to use them to power a usb power bank. My problem is that I measure output voltage from 3,5 to 6V. When there is a cloud, voltage is not enough and when there is full sun I get a little too much. (Is it fine to charge at 6V instead of 5V through USB ?) I would like to know if there is a simple way to regulate the voltage to 5V and to let the current fluctuate with the sun instead of the potential. Ideally I would like to keep usb connectors (to avoid soldering, wiring and modify the circuit easily) but any idea is welcome. Thank you :)

Question by MathiasLeroy 4 years ago  |  last reply 4 years ago



DC motor regulation

I am planning to build a small gearbox that depends on a steady rpm from a 3V dc motor. I understand that the output rpms will change in correlation to the fluctuation of input power. My question is, if I used a regulator to regulate the input voltage from 5V to 3V, will that keep the motor rpms steady?

Topic by Tman179 1 year ago  |  last reply 1 year ago


How do I set up a voltage regulator? Answered

What is the connection ADJ in this image of a voltage regulator stand for? Is it just the ground, or something else?

Question by Spacew00t 9 years ago  |  last reply 9 years ago


Voltage regulator to get from 70vac back to 120vac?

Hi all, I am using (and for strange reasons am required to use) track light outlet adapters to power some LED light strips. The LEDs use an AC adapter that requires a minimum 100vac to run properly. The problem is that the track lights are dimmed substantially, so the voltage coming from the tracks is only 70vac. Any idea what I can use to bump the voltage back up to the 100+ voltage range? Tripp Lite has a some regulators, but they don't go down to 70vac. APC makes one that goes down to 80vac, but that's the lowest I've found. Is there an off-the-shelf regulator that goes down to 70 volts? I found this contraption that looks promising and maybe a little sketchy (alibaba style). Any other recommendations? I guess the other question is what is the risk in running the LED strip lights if their AC adapters are getting 30v lower than they recommend? The lights appear to function fine, but will the adapter overheat? Burn out quickly? Cause a fire? If it burns out, say, once a year, I'll probably leave it, but I have no idea what the consequences are. Thanks in advance! 0    ..    o uuuuuu nnnnnn

Question by uuuuuunnnnnn 5 years ago  |  last reply 5 years ago


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 2 years ago  |  last reply 2 years ago