Powering LEDS with mains power.

What if you made a voltage divider with high-value  resistors, and then rectify the signal?  Is that dangerous?

Topic by flagrantfouler 8 years ago  |  last reply 8 years ago

Powering LEDS with mains power.

The idea is to use a voltage divider with high value resistors and then rectify the signal.  Is this dangerous?

Topic by flagrantfouler 8 years ago  |  last reply 8 years ago

Power Electronics: power converter Answered

I have been running through example questions for an exam I have coming up; the following picture is a condensed version of half a page of working. My lecturer gave us the solutions and a few steps between beginning and end to get to the solution so we could work it out. However, as you can see the picture below I got 30.6A whereas she wrote 54.2 down. The problem is to "Find the maximum values of the average" (done this bit) "and rms thyristor currents for any firing angle, alpha.". The values of R and Vs are in the diagram. Alpha is assumed to be 0 since then the thyristors will conduct for the greatest possible length of time. I think she may have got to the end then forgotten to square root of Pi before multiplying Vm/2PiR by it. Does anyone agree?

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

Wind Power?

Rather than charge batteries, can an inverter be used to run the power from the turbine to the grid?

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


I was just wondering what are good places to buy power tools from, thanks.

Topic by TREX ZoaR0K 5 years ago  |  last reply 5 years ago

Power outage? Answered

Would like some suggestions as to how to circulate hot air from wood stove in one room to other rooms in home, when the power is off We usually use Fans when we have power.

Question by emit 9 years ago  |  last reply 8 years ago

Power Suppy Answered

I need to make a 6.5 vdc - 500ma power supply I have no clue how to make it 6.5v. any help is deeply appreciated

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

isnt powering on?

Have replaced a ds shell, but the power button dosnt work it feels as if it should have grip of something as it feels to free,?

Question by rodelesk 9 years ago  |  last reply 8 years ago

Power of a ramrod

Hello guys, I'm working on a knex gun now, but I have a question about how to get the max. power out of a ramrod. So when does the ramrod give the most power: • 1: The ramrod hits the ammo and doesn't go further • 2: The ramrod hits the ammo and still goes (a couple of centimeters) further Thanks in advance, Bobbienator

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

Power Suit

Lets make a power suit: some one please make a website and make me the leader and we could make this power suit to make our future better. send email to me when you make it scarygyujosh@gmail.com no spam please!!, maker the site name powersuit.net

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

lcd power? Answered

Does anyone know the average power impute on a LCD display i need to test its backlight

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

power hack

Aside from it being an ugly hack, is there any reason I can't strip the wire back from the end of a printer power cable and solder it to the plug terminals of a 5v wall wart transformer? This shouldn't be a fire hazard since the power cord should be rated correctly, correct?

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

Power supply?

Since I was thinking of building a bipolar power supply +12V, -12V, using a 12-0-12 transformer and using only diodes and capacitors, which I have successfully built. My problem is how safe can this power supply be? since I am not using any regulators?

Question by VAustin89 7 years ago  |  last reply 3 years ago

powered speakers

Hello im realy new to the electronics game and i was wondering if anywas can sow me a REALY SIMPLE diagram of where wires should go to get powered speakers i have 2 speakers and want to power them by battery so a nice little circuet diagram would help:)

Topic by wii maniac 11 years ago  |  last reply 11 years ago

Power problems

A friend of mine recently blew a fuse and now his desktop isn't working. Is there anything I can do to to help him so he doesn't have to get a new computer?

Topic by computerfaker3 10 years ago  |  last reply 10 years ago

Laptop Power

Hi all. I have a really old dell laptop(given to me) that is missing a power supply. It requires 20v and 3.5 amps to run. I want to make a digital picture frame out of it. I wont be using the battery or cd player and maybe not even the hard drive(not yet decided). Any idea's on what to use as a power source? I don't need to charge a battery just need power. Could I use an old pcu? I know that I could combine the two 12v lines to get 24 ish volts but won't that fry the old thing? I don't want to buy a replacement power adapter cause it is so old and may not work anyway(plus I wont lie I'm cheap lol). Any suggestions?

Topic by jmiller634 6 years ago  |  last reply 6 years ago

Wireless Power?

OK so recently I have noticed that almost any sort of power can be converted into a different type, sorta. Anyways, it takes power to create radio waves or any wireless wave. Would it be possible to just send out plain radio waves and get something to pick them up and convert them into usable power? Now I know the farther you were from the source, the weaker the power would get, so you might have too send out a fair voltage signal to get some good range. Also, would it interrupt any electronics in range or anything like that? I was just thinking about this and wondering if it is even possible to get actual wireless power around your house or something without using batteries or interrupting anything in your house. Thanks.

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

Wireless Power

----- Click Here for Full Story -----We may be able to say goodbye to power cords in five years, as Intel has developed a system called WREL (wireless resonant energy link) that could possibly run electronics without having to find a wall socket."Wouldn't it be fantastic if we didn't think about where the power was coming from and the power was everywhere?"said by Intel boss Justin Rattner in an interview with BBC. Rattner explained that through Intel's idea of "magnetic induction", the power source can be tuned through a resonator, enabling gadgets to receive power wirelessly. The report further explains:"Power is put into magnetic fields at a transmitting resonator - basically an antenna. The receiving resonator is tuned to efficiently absorb energy from the magnetic field, whereas nearby objects do not."Of course, there would be issues at hand if Intel's technology breaks through the mainstream. How are companies such as Monster Cable going to fair if this new possibility rises? Well, we'll just have to see until then.Just how long till someone makes this cheap?

Topic by Keith-Kid 10 years ago  |  last reply 10 years ago

Battery power

I have a battery powered laser on top of a spinning disc. This laser runs out of battery fairly quickly, I need to make it last longer somehow. Could I wire the laser to multiple batteries to make it last longer? If i manage to find a mains powered laser then it spinning constantly wouldn't work as it would have a wire. I ideally need to find a way to power this laser (probably 2 lasers) for most of a day with something that fits on a fairly small spinning disc. Any ideas? Cheers

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

rectenna power

Im trying to find some practical build instructions or something to clarify how to do this in my own mind most of what ive found is not helpful any input would be apreciated im trying to build one for a ardrone

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

power question ? Answered

I need to get 36volts for something in my boat. How can this be done? Cant fit anymore battires. Easiest way to stepup 12volts to 36 volts.

Question by kurt1968 6 years ago  |  last reply 6 years ago

Powering LEDs?

What I am trying to do is built a LED board that beats to music.  I have found many way to make it beat to the music, but my problem is I don't understand how to power the LEDs.  I am new to building electronics, and I am still learning.  Anyways, what my hope to do is use build a board 46in long running one LED per inch.  This will be dived up into smaller sections to run different beats off my home theater system.  I am trying to run all of this using  4 TIP31c, and I understand how to use them, I just am not sure how to power this.  Thank you!

Question by Togroovy4u 6 years ago  |  last reply 6 years ago

iPod Power ... BUT!

Here's the challenge:I have a Belkin SportCommand iPod Remote and it works great. However, it uses the iPod's connector port and draws its power from the the player. I have this thing installed on a waterproof boombox that needs to play tunes for 8-10 hours at a given time and I don't want to have to open the box AT ALL (lots of water + electronics ...).So, I need a way to have both the iPod accessory plugged in and, at the same time, charge the iPod from a 12v power source (like most car stereo iPod adapters do. I think this is as easy as a little plug to go inbetween the iPod and the accessory, but I can't figure out which pins to tap into. There are a lot of different power pins on the connector, and I need to know which two (ground and V+) are the *charging* inputs.Ideas/suggestions/comments? Thank you!

Topic by tridens 11 years ago

CD's for power?

I was cleaning my room and found a load of blank CD's. It made me think of all the AOL discs that my house used to get. So I got to thinking - There's a lot of power wasted on these things, right? So, my job for you, Instructables users, is to help me engineer a way to use these CD's to generate solar, wind, tidal, geothermal energy, whatever. Anything renewable. Any ideas?

Topic by A good name 8 years ago  |  last reply 8 years ago

USB power? Answered

I have a 1.2 V nimh battery and a 3.7V li ion (no protection circuitry) battery, which would add up to 4.9V if put in series. However, I want to turn it into a temporary USB power supply (5V) so ignoring all the things regarding putting 2 batteries of different capacities together, is there a way to kick the voltage up a tiny bit? I was thinking something like filtering the output of a joule thief, possibly. I also have a solar panel (4.5V, ???A) and was wondering if that could help, but I don't want to rely on it too much.

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

DC power + or -? Answered

I have looked at lots of Instructables and websites, but there is a 50/50 split that power flows positive to negative and negative to positive. Which is it? I use both, depending on the circuit I am building it is easier to build one way over the other (NPN and PNP Transistors usually) But I have heard that it used to be thought that positive flowed to negative but I have since heard that the new idea is that it flows negative to positive. I know that everything is supposed to flow from higher concentration (+) to lower (-) but we could have batteries labeled wrong so I don't know. Very confused.

Question by Electric Spectre1 9 years ago  |  last reply 9 years ago

transformer power

I have been thinking about this for a long time now and in therory it works.  What im wordering is if you could make it work in place of the traditional power outlet.  Here it is, basicly there are just coils of wire inside of a transformer, on coil has say 240 turns of coil. Inside of this coil is another coil with 240 turns also.  So the voltige inside the first coil will be the same as the second coil.  And to half the voltige in the first coil.  If you had a plug that was just a cilender with a coil of wire inside and an outlet that was a hole in the wall with a coil inside.  I know a hole in the wall with 120 volts running through it sounds scary , but put a plastic cylinder inside the hole and vurtaly no shock hazerd. sorry for the spelling errors spell check was not working.

Topic by Laserman595 9 years ago  |  last reply 9 years ago

The power of C.A.D.

This is what happens when I get my hands on C.A.D!!!! And this is a pic of the RC plane I am in the works of designing. I dont have the ratios to make everything the proper size so I had to estimate. I plan on having it done by the end of my school year in September.

Topic by Pat Sowers 11 years ago  |  last reply 1 year ago

Capacitor Power

I want these so badly, and I live relatively close (about 300 miles away).http://cgi.ebay.com/Qty-46-Pulse-Capacitors-7000v-230uF_W0QQitemZ200268515465QQcmdZViewItem?hash=item200268515465&_trkparms=39%3A1|66%3A2|65%3A15|240%3A1318&_trksid=p3286.c0.m14You can make one heck of a capacitor bank, releasing almost half a megawatt in a split second.My only problems:I don't have 1600 dollars, crycry.These things are so large that if I were to line them up side by side (so that the thinnest parts create the overall thickness) it would be 25 feet long, 14 inches wide, and almost a yard tall. THE POWER BOGGLES THE MINDI'm so mad, if I was an adult I'd buy these in a heart beat... sigh... deal of a life time... I hope not...and best of all, they are PULSE CAPACITORSthoughts? comments?

Topic by guyfrom7up 10 years ago  |  last reply 10 years ago

Battery power

I am attempting to calculate my amp need for my garage in order to set up a 12v battery system. Using the formula; Watts / voltage = amps drawn, I have hit a question. If using a 12v battery system and converting to 110v, should I be using 12v or 110v in the formula?Example; 100 watt light bulb / 110 volts = .91 amps. Nice!But if I use the 12v; 100watt light / 12v = 8.3 amps.I'm believing I would be drawing 8.3 amps from the battery to power this light.Plus the converter draw...Please tell me which is correct?

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

solar power?

I want to get these 12v solar battery chargers they come with alligator clamps to hook to the battery. i want to get enough for 200 volts so how would i hook the solar panels in series, and do i need a controller for each battery? and how would i rig that up and how can I get it going into all the 12 volt batteries without any damage to the batteries etc. And can this be done for less than $400 if the solar panels are $30 each and the batteries are $14 each. THANK YOU!!!!  THANK YOU!!!!  THANK YOU!!!!  THANK YOU!!!!  THANK YOU!!!! oh and could you give me links for all the stuff I'm gonna be buying. THANKS!!!!

Question by jimmerforpoy 8 years ago  |  last reply 4 years ago

The power of the mind...

I cdnuolt blveiee taht I cluod aulaclty uesdnatnrd waht I was rdanieg. The phaonmneal pweor of the hmuan mnid, aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it dseno't mtaetr in waht oerdr the ltteres in a wrod are, the olny iproamtnt tihng is taht the frsit and lsat ltteer be in the rghit pclae. The rset can be a taotl mses and you can sitll raed it whotuit a pboerlm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe. Azanmig huh? yaeh and I awlyas tghuhot slpeling was ipomnartt! Can you understand this? Does it make any sense? I know I could read it. Can YOU? NOTE: Yes, this is more legible than certain Instructables and forum topics are. Irony?

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

Power supply

Last time I tried to do my own homemade project I failed utterly, I think mostly because I had no idea what anything was (if you saw my last topic on a distortion petal, you know what I'm talking about). I decided instead to buy a book (Tab Electronics Guide to Understanding Electricity and Electronics by G. Randy Slone) which has projects in it, the first one being a power supply. I haven't started building it yet (waiting until I get back to the city) but I've started looking up parts. The thing is, I can't find a 4400-uF 50-WVdc capacitor anywhere! So my question is, can I just put two 2200-uF 50-WVdc capacitors in parallel to do the job of one of the 4400's? That isn't my only question, just the first which I'll ask later in this thread. Thank you (PS: Has anyone had a problem with using Chrome and entering text into these fields? I had to switch to Firefox to get it to work)

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

Latino Power

Abro este foro en celebracion de la inclución de los nuevos países de habla española como admitidos para poder participar de los concursos y retos. Sientanse libres de compartir sus proyectos en español . Recordemos que somos ciudadanos del mundo. Hagamos sentir la magia y creatividad del Poder Latino ! Take that Mr. T. https://www.instructables.com/id/Walnut-SeasonTemporada-de-Nueces/ https://www.instructables.com/id/SAWDUSTOVEN/ https://www.instructables.com/id/HAWKEYE/ https://www.instructables.com/id/DIY-Hobbitss-Pipe/ https://www.instructables.com/id/Black-Walnut-Seed-Ring/

Topic by Mr.Sanchez 2 years ago

Converting mains power to battery power?

I have plans on building an electric go cart, however, the only motor I currently have is mains powered, as such I was wondering if anyone knew of any ways to convert mains powers to battery power, hopefully car batteries as these would be what I using. I've searched high and low and can't seem to find anyone that has done this, let alone a tutorial. Anyone with any idea's or links would be very helpful. Thanks in advance.

Question by ads100 9 years ago  |  last reply 9 years ago

Converting AC power to DC power

I have a question about converting AC to DC using only two Diodes. I know you can have one transformer with a center tap and use two diodes. The question is, if I have two transformers connected in series to each othercan I do a center tap between the transformers and still use two diodes? The transformers both have the samevoltage out put. Thanks for any help

Question by tom1933 10 months ago  |  last reply 10 months ago

Battery power and power consumption help!

I have a geocache project and need help with the power supply and power consumptin inside it. The basics of the project: It is a large wooden box. The box has a on/off switch. It also has various various coin slots. Flip the switch, turning it on, to supply power to the solenoid inside. Dropping a coin through the correct slot will trigger a momentary micro switch which activates the solenoid and springs out the drawer of treasures. Take your loot. Close the drawer. Turn off the switch and leave it for the next adventurer. And it works! Yay! Commoonents the question:  The solenoid is a 12v  door latch solenoid. https://www.adafruit.com/products/1512 The battery is a 12v 5ah sealed lead acid battery.  The coin micro switch is: https://www.adafruit.com/products/820 My question. This geocache that lives, protected, about 3 blocks from my house. I obviously won't be charging the 12v battery very often. Since this setup only has momentary power draw once in a while. Say once a week. Maaaaaaybe. Does anyone have any alternate power recommendations? I am okay with changing out the batteries once in a while. But I'm hoping for a once every few months. I originally used a new lead acid battery but it seems to have died. Possibly from letting the charge fall to low and then sulfation occured. I'm considering using a 11.1V Lipo Rc battery instead so I can recharge it at various levels of depletion. Thing is I need it to last a worth while amount of time without loosing power but also killling the battery from just sitting there.  Thoughs woukd be GREATLY appreciated.  -McG

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

power wheels too much power?

So here da ting. i got a little 6v power wheels quad at a yard sale for dirt cheap. i figured hey why not ill work on it a little and make it nice. long story short, i ended up with two 18v harbor freight batteries hanging on each back fender like military ammo cans and it looks awesome but now its a little too scary to let my son ride it. i would like to put a voltage regulator on it to turn it up or down depending on how well he can ride it and how safe i feel he can be. most of the ones i have found can barely handle 2 amps. where can i get a regulator to handle the load continuously. p.s. this is the last part i have to figure out before i can make a full instructable.

Question by snowfox222 2 years ago  |  last reply 2 years ago

Looking for a schematic for a bright, LED, solar powered, outdoor light?

Hello,  I am looking to make a pretty bright, solar powered light, for use in the yard.  I have a very bright, 3 LED flashlight, that uses 3 AAA batteries.  I would like to make a light for the yard that has 2, or or more LEDS to light the sidewalk. Any assistance would be appreciated.

Question by Big Pics By Steve 9 years ago  |  last reply 9 years ago

can you change household items that plug into the wall to battery powered?

I was wondering for a few reasons if this could be done and if someone with skills in this department to tell me n how to do saflety please i wud be really greatful for any comment......

Topic by jp_cfc06 11 years ago  |  last reply 11 years ago

i want a solar powered battery which can store the energy for a long time- 1 day and it shud b fitted into an garment.?

Actually...i want one solar powered battery that can store the sun energy for a longer time.and can b later used.example:- like in the hillly regions..u dnt get power supply , so u can charge while downhill and use it when we can to hilly regions...ie it wnt b able to give sufficient solar energy...in that case i need one...and it shud b fitted into the garment.

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


Hey  does anyone wanna be my friend on steam?

Topic by builderkidj 7 years ago  |  last reply 5 years ago

7v from 12v?

I need to run a 7v / 1.6 A DC water pump and a 12v / 1.13 A DC fan from a small portable battery pack. If I use maybe 8 "D" cell bateries, do I need a converter to power the 7v pump or will it work with 12v? Thank you,

Question by fastrack777 9 years ago  |  last reply 9 years ago

Wind battery charger and heat up a copper wire?

Is it possible to heat up copper wire with a small wind turbine and also charge a battery at the same time please help thanks dean 

Question by Deano1247 7 years ago  |  last reply 7 years ago

"flasher" or strobe or similar for battery

Hi, I'm kind of new to this and don't know what I want, but can describe it.  I'm looking for a small, inexpensive device that will turn a battery off and on.  I have a battery powered electromagnet that moves a clamp.  I want to make something like Clamps from Futurama where the clamp just opens and closes on its own about once every two seconds.  I've got the battery, battery cover, and wire leads on that end.  I've got the clamp, wires, and normal on/off switch on the other.  I just need the bit in the middle.  I can use a regular on off switch, but I don't want to have keep constantly flicking it off and on. All of my google searches end up pointing to either strobe lights, car electronics, or Christmas lights.  None of which will really work. Any ideas of what this would be or where to get a couple cheap? Thanks!

Topic by BobR90 2 years ago  |  last reply 2 years ago

Solar powered Cthulhubot

Cthulhu, one of the Great Old Ones, is now green.Etsy member tinyminds has made a solar powered Cthulhubot. It remains dormant while it soaks up sun rays, but when its had its fill of energy, it begins to flail its tentacles all about while the mere mortals scream and shout.Link via BoingBoing

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

purpose of mousetrap powered car?

For science project need the purpose of themousetrap powered car

Question by diegodelrio 10 years ago  |  last reply 9 years ago

Solar powered cooler

I'd like to make a solar powered cooler, however, I am extremely new at this.  I was thinking I could just purchase an electric cooler and a solar panel with the voltage needed, and simply attach the wires.  I feel like that is way too simple to work but I don't know what else to do!  If anyone has any suggestions, I'd greatly appreciate it! The cooler I was thinking of using is here: http://www.amazon.com/Koolatron-W75-Wheeler-Cooler-36-Quart/dp/B00267SQVU/ref=sr_1_11?s=automotive&ie;=UTF8&qid;=1340659801&sr;=1-11&keywords;=thermoelectric+cooler  and the solar panel: http://www.walmart.com/ip/Moultrie-12V-Solar-Panel/16386235 Thanks!

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

low power razor scooter

So I was riding my small razor scooter to school (the kinds that fold up and fit in a backpack) and thought "it would be really cool to make this thing run with a motor." After I got home, I looked at it and thought of a way to make it work. If you put a small rubber piece on the end of the motor and lay that against the wheel right behind the break with some pressure, you could probably make it go pretty fast. The thing I was wondering is what is the smallest motor I could use and still have it work at about the same speed as me pushing with my foot on the road? 50 watts or so? I only weigh 125 pounds and would like it to work with 150.any suggestions? I would like to not have to use a car battery, with all the balance issues and such.

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

Has anyone tried air power?

I have been experimenting with compressed air. Currently I am working on a compressed air turbine. So far it so promise. I'm running a 18" x12" casing. It turns about 10,500 rpm and runs through a gear reducer to provide torque that I need to run a generator. I have a small screw compressor to refill the tank.

Question by alvin9861 8 years ago  |  last reply 8 years ago