Is there a difference between a 7805 regulator and a LM7805? Answered

Lm7805 http://www.sparkfun.com/products/107 7805 http://www.radioshack.com/product/index.jsp?productId=2062599#

Asked by Munchys 7 years ago


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 curious...is 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!

Asked by DoctorWoo 5 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?

Asked by DELETED_afw11 8 years 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?

Asked by imakethings 8 years ago


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

Posted by gungfudan 5 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?

Asked by XOIIO 5 years ago


I wan't to know about the speed regulating device known as a governor.

It's also known as the centrifugal governor.It is used in vehicle engines.It's function is to limit the speed of a mechanically driven device.

Asked by ammarasheed 8 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?

Asked by -max- 2 years ago


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!

Asked by mckywer 7 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...

Posted by lone_viper 6 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...

Asked by lone_viper 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 

Posted by starvin 6 years ago


Pls Help me!!!can i hold 12v dc and 24v dc? can i be grounded?

Pls Help me!!!can i hold 12v dc and 24v dc? can i be grounded?

Asked by axdsqzwer 6 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.

Asked by RajeshM64 1 year ago


Where find 5v regulators?

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

Asked by ondrikczech 5 years ago


PYROGRAPHIC TOOL HEAT REGULATOR

How Can I make a Homemade pyrographic heat regulator using salvaged parts??

Posted by smallludwig2 10 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

Posted by frankv6 2 years ago


Help Making 6V regulator?

I need to power one of my projects for which I need a power source. I require 6V,which will require a lot of batteries. So, I decided to make a regulator and supply it through my 12V DC transformer. Please if any one of you can give me a schematic of the same I will be gratefull.

Asked by pranjal12 5 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!

Asked by raykholo 7 years ago


Needing Schematic for a High Amp Power Regulator

I have two transformers ( 430-7101A) that're wired together from a APC Battery Back-up that I'd like to turn into a high amp regulated power supply. I've been looking through the site and have seen very few options. I'm positave that (sorry for the pun) there's a shematic somewhere out there and would Love to get my hands on it. These are a very nice pair of transformers that I'd Hate to see go to waste. And help would be Great! TIA

Posted by your_dragon113 5 years ago


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. http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=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?"

Asked by flybye22 8 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 :)

Asked by MathiasLeroy 3 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

Posted by blakea 4 years ago


May I be advised on powering cheap lasers from this device? Answered

I've got a "6V" SLA connected to it's original charger. It's currently driving a motor with a mirror glued to it, I want to add a couple of cheap laser modules to the same power supply. >SLA  charges at over 7V >No load voltage is less than 6V >When running the motor the voltage across the terminals is less than 5V I do have a couple of UA79M12C -ve voltage regulators, and think I should use one. The cheap lasers are built to run from 3 button-cells (~4.5V) Advice appreciated L

Asked by lemonie 6 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.

Posted by V-Man737 9 years ago


strange motor driver (early stepper?) what do you think?

Hello everybody, i got this motor out a damaged cine cam.playing about attaching power to the trailing wires from the board i get 2 speeds. orange -0v green +6v high speed brown +6v low speed motor makes a nice thrumming noise as it runs.looking forward to using it in something. putting power direct to the motor wires is quite unresponsive. going to try a pot between the 2 +ves that, work maybe getting variable speed. (puting the +ves together got the same high speed as just the green wire) anybody recognize this system? know how it works? thanks

Posted by crazyg 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.

Asked by pollock9131 7 years ago


2 Voltage Regulators, 1 Power Source?

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

Posted by flagrantfouler 8 years ago


Use a Co2 regulator for air?

Can I use a Co2 regulator to regulate high pressure air.  I am trying to build a high pressure system using a scuba tank or paintball/airsoft tank to operate air tools, pressurize pipes, fill tires, inflate balloons, dust work areas and computers, etcetera.  There are C02 regulators but not many 'air' regulators.  I just want to use air and not Co2.

Asked by RandallIja 8 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

Asked by lemonie 5 years ago


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

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

Posted by Dread_Neck 7 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?

Posted by lolkent 6 years ago


Can I replace the transistors in this LM723 regulator circuit with MOSFETs? Answered

I am trying to build a power supply capable of outputting up to 15V at 10A. The heatsinks I have are not suitable to use with the 2n3005s TO-204 case. Also I can get IRFP250 MOSFETs a lot cheaper. The transistors I want to replace are Q2-Q4, Q5 I will not include because I only want 3 FETs because I only want a 10A supply not a 20A.  Here's the link: http://www.thebackshed.com/forum/forum_posts.asp?TID=2249&PN=2&TPN=1http://www.thebackshed.com/forum/forum_posts.asp?TID=2249&PN=2&TPN=1

Asked by The MadScientist 5 years 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?

Asked by Spacew00t 8 years ago


Gas regulators, which one to use?

I've recently had two gas questions arise. Both issues need a gas regulator that I am not sure of what type, or pressures needed. The first a a L.P.G bunsen burner I bought off ebay. The second, I have a gas furnace for smelting that connects to L.P.G Can someone give me some help on what type of regulator I need for these? Also maybe a bit more info on how to connect the bunsen burner up to the gas bottle, regulator, to a switch valve, then the burner. I have seen low-pressure regulators about as well, can this work for the bunsen burner

Asked by AtomRat 5 years ago


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.

Asked by Chirishman 5 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

Asked by uuuuuunnnnnn 4 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.

Posted by menace 8 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.

Posted by .conne. 10 years ago


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

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

Asked by zack247 6 years ago


Can I use a AC switch in my DC project? Answered

I'm trying to install LED lights in and around my car. Can I use a AC switch in a DC circuit/system? The AC switch is rated as 10A 125V AC / 8A 125V / 4A 250V AC / 1/3 HP 125V AC. I plan on putting the switch between the 12v DC car battery and the 12v DC to 5v 5a DC regulator (which then powers the microcontroller and LEDs). Is this doable and safe?

Asked by anuvanoob 3 years ago


Attention Electrical Engineers and Physicists! Light bulb as current regulator?

A light bulb can work as a current regulator right? If I understand correctly, an incandescent light bulb conducts with negligible resistance until it reaches a critical point at which point it resists any more… More what? More current? More voltage? The situation is this: I have made an AC arc welder out of microwave oven transformers but I have no control system. This welder works great for about an inch of weld then starts blowing the breaker until it cools off. (You’d think it would be the opposite with resistance increasing and current decreasing as the coils warm up, but it’s not… Why?) So what if I put three 500 watt light bulbs in parallel with each other but in series with the welder? Could this work as a 1500 watt current regulator? And if I did this, where should I put the bulbs? Should they be in series with the 110v side of the transformers or on the ~40v side of the transformer? I figure they should be on the 110v side but then they’d be on all the time, heating up the primary windings, right? Or should they be in series with the secondary windings? This way they’d only be in when I’m actually welding but they’d have to conduct a lot more amperage. What would jyou do?

Asked by snotty 5 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?

Asked by codestroy7 5 years ago


Free electricity for a bicycle headlamp

A really good bicycle headlamp needs quite a bit of electricity to make it bright and last a couple of hours. A dynamo requires extra leg power to operate. Yet, there are power distribution lines along the roads where I ride and they emit electro-magnetic lines of force. Imagine a coil of wire on the bicycle that follows the triangle portion of the bicycle frame and it receives these lines of force, converting them to a low voltage AC current. That current would then be passed through a bridge rectifier and a voltage regulator to charge normal size flashlight cells powering the light. Technically, it is probably illegal. Certainly it would be if you were using a coil of wire on your lawn positioned under the power lines to power your house. If it could be done safely, the power company would have a hard time tracking you. It is probably impractical, but it is interesting to ponder.

Posted by Phil B 6 years ago


Voltage regulator? Answered

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

Asked by .Unknown. 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

Posted by mrshow555 10 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?

Asked by Ahtasham Ahmad Mohtashim 4 years ago