### 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   |  last reply

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   |  last reply

### 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   |  last reply

### 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   |  last reply

### 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   |  last reply

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.   |  last reply

### 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   |  last reply

### 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   |  last reply

### 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   |  last reply

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

Question by MACKattacksnipe   |  last reply

### 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   |  last reply

### Power Supply

With this circuit, does it matter how many amps the input is rated at? The output is supposed to be 2 amps at 9 volts

Topic by TheLostAmish   |  last reply

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   |  last reply

### 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.

### power pack for battery powered mp3?

I am wondering if its easily possible to convert a mp3 that runs on AAA to mains via a power pack, which we all seem to have plenty of laying around. i realise that the AAA battery is 1.5v or there abouts while the closest spare power pack i have is 4.0v dc / 350mA will it work, or is it possible to further step down so it would be suitable ? via electonics - or do i need to find a powerpack that matchs a AAA battery voltage. i was going to wire this to the battery terminals ... or am i just looking for trouble? lol

Question by agatornz   |  last reply

### Power phone on the battery with usb power?

Hi! I plan to make my old phone as a wifi booster. The only problem is that the USB "hole"/socket is borken. So I came up with a solution: I added + and - from a usb cable and then placed it on the phones battery. Should I worry if it touches the middle thing of the battery? I mean that thing between + and - . I think it won't if I place it carefully in the phone. I will connect the USB cable from my PC as I don't want to do it with strong power from the power point. So should I worry with the USB power from the pc  if something goes wrong?. [b] Should I go with this or not?..[/b] I hope you understand I wrote this very fast, I can re-write if you don't understand thanks!.

Topic by Davve95   |  last reply

### Human Powered Bike Powered Generator?

HI, I am an artist and I am creating a bike powered led sculpture for kids at a museum. I need some help making the connections correctly and finding the correct electric motor and volts not to over load the LED light bulbs as well as how to figure out the easiest gear ratio for kids to turn, There will be five 60 Watt  /120 Volt LED bulbs connected to deep cycle car battery (used as a voltage regulator) that will be connected to a stationary bike pedaled by visitors to display the human energy potential. I want to figure out what type of electric motor I will need for those lights and how to make the gear ratio for the bike easy enough to turn for kids... Any knowledge on these calculations will help. Thank you ! Jessie

Question by real_jessie   |  last reply

### 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   |  last reply

### Higher powered speakers with lower powered amp or Low powered speakers with higher power amp?

There is a lot of conflicting information on this and I would like to know if my speakers/amp would get damaged. Using 80w speakers and a 50w amp will there be any problems with running on full volume? And if I got a 100w amp with those 80w speakers will there be damage, even if I added a heat sink to the back where the voice coil is? The speakers say 80w max but not really reliable as they are well priced Chinese speakers. Speakers: 80W Audio Sensitivity: 88dB Frequency Range (Hz): 100-20Khz 4 Ohm Amp: Efficiency: 90% Rated output power: 2*50W+100W Working voltage: DC18V to DC24V The maximum output current: 4A Frequency Response: 20Hz-20KHz Can drive a 3-16 ohm speakers In the condition of rated voltage 24V The sub woofer channel at rated voltage 24V state can drive 2-16 ohm sub woofer Bass cut-off frequency independent regulation 20HZ-20KHZ adjustable Very confusing conflicting info online with under rated amps causing clipping and over powered amps frying the speakers. Originally I thought it was only bad to over power the speakers. Any help about what is worse, is appreciated.

Question by bonze77   |  last reply

### PC Power Supply To Power CB Radio?

I have a cb radio my uncle gave me 12v 2-4 amps.. I have an old computer with a power supply with lines for 12v 6amps and 12v 8amps. is there anyway I can get this to power my cb radio without blowing the thing? EDIT I forgot to mention, this is a mobile cb radio, I'm trying to run it in the house, which is why I wan't to use a pc power supply to run it....

Topic by acer5050   |  last reply

### The electronics for powering a pump via solar power

So I've been tossing around the idea of making a automated garden that uses solar panels, much inspired by a vermiponics instructable I saw but I have some questions of theory and practice I'd like help with before I go into it. I've worked with simple electronics and have a fairly good grasp on the theory but nothing quite this complex or with components I'm not familiar with, so I'm looking for advice. 1) Solar panels must need something like a capacitor or battery to store the energy for the motor to use, and how would I get this reservoir to trigger at a high enough voltage so that the motor can actually spin and I don't just end up with a motor charging a battery that is discharging across a motor at a low enough current that it doesn't spin. 2) preventing the battery from discharging back into the panel, I assume one would use a diode for this but I'm curious if there's anything additional that is required 3) If I wanted to try adding further automation by adding an arduino with a mess of sensors, would powering the arduino from an additional battery charged by the same panel work (I assume this would slow down the charging of the motor's battery). 4)  Safety features to implement so I don't do things like overcharge the batteries/ suggestions encouraged. The arduino is currently gravy for the project, worst comes to worst I can set up some simple level switches.

Topic by squirrelchaser   |  last reply

### Battery powered arduino + high power leds?

I'm desperately trying to design an arduino circuit that can power each color of a high power cree MC-E color RGB led. What is the smallest dimension rechargeable battery I can use to accomplish this and have it run for a few hours? I'm desperate!

Question by SpiffyChee   |  last reply

### how to power a 30w high power led? Answered

I order a 30w led from ebay but i dont know how to power it can i use just a 16v 2a power adapter or hove i to buy a led driver here is the led:             http://cgi.ebay.com/30W-White-High-Power-2100LM-LED-Light-Lamp-Bulb-A_W0QQitemZ220708010099QQcategoryZ163866QQcmdZViewItemQQ_trksidZp4340.m263QQ_trkparmsZalgo%3DSIC%26its%3DI%252BC%26itu%3DUCI%252BIA%252BUA%252BFICS%252BUFI%26otn%3D10%26pmod%3D220693236934%26ps%3D63%26clkid%3D5621333683761900258

Question by Andrew_48   |  last reply

### How to power a High power laser diode?

If I build a 42A Constant Current PSU which can supply 1.2-6v, will the laser diode only draw 1.8-2V or will it try to draw to much voltage and damage its self? I have a 40W CCP CW Laser diode, here are some characteristics. Operating Voltage (V) <2.0 (1.8 typ.) Operating Current (A) <46 (42 typ.) I know that laser diodes will try to draw as much current as possible and suffer thermal runaway, so they need constant current power supply's. If anyone has any information on how to power high power laser diodes please let me know. All help will be greatly appreciated!

Question by deltawars   |  last reply

### how to power a 30w high power led? Answered

i am making a diy homemade projector and i want to know how to power a 30w led without a driver becouse the driver cost 30\$ and i want to make the projector as cheap as posible so if anyone know a way to power a 30w led without a driver please help me the led ......http://cgi.ebay.com/30W-White-High-Power-2100LM-LED-Light-Lamp-Bulb-A_W0QQitemZ220708010099QQcategoryZ163866QQcmdZViewItemQQ_trksidZp4340.m263QQ_trkparmsZalgo%3DSIC%26its%3DI%252BC%26itu%3DUCI%252BIA%252BUA%252BFICS%252BUFI%26otn%3D10%26pmod%3D220693236934%26ps%3D63%26clkid%3D5621333683761900258

Question by Andrew_48   |  last reply

### Substitute of Power Transistor

What is the substitute of 2N6292 power transistor? Please suggest a good substitute of 2N6292.It must be an NPN power transistor. Thank you.

Question by SiamB1   |  last reply

### PSU Power Supply

I built a PSU bench power supply, but it isnt outputing the right voltages. It just out 5v for all lines(12v,5v). It has a purple wire that is said to be the stand-by, but the psu wont start unless it is connected to the 12v or 5v line. It also says that you have to have the brown sense wire attached to the 3v wire but this seems to do nothing. How can I make this thing output the right power(12v @ 22A, 5v @ 50A)?

Topic by tylerb   |  last reply

### led powering question

I am building a garduino since planting season is coming near and this would be a great to start me seedlings off in. right now I have 3 banks of three red leds rated at 1.8v and in one of he instructible they said 7v was sufficient but i am connecting a 9v and can only power 2 leds and also I would like to go with an ac-dc converter but everyone i found has at least 800+ mA can someone point me toward a good power supply at the end I am looking at about 25 red and 8 blue LEDs

Topic by redwind   |  last reply

### Small power source

I was planning to make LED jewelery, but would need a very small power source. In the best case it could be powered by the body's movement. Is there anything small enough to bit on a wrist, yet can power about 10 LEDs?

Topic by DemonDomen   |  last reply

### A/V + Power Switcher

I think it would be beneficial to create an A/V switcher that has power plugs for each of the slots in addition to the a/v components. So if you select #2 for example, it would power only #2 as well as display whatever is plugged in to #2. Could someone create a tutorial for this? Thanks

Topic by evillordnikon

### power supply cooling

Normally I'm pretty good with electronics, but I need some help with this problem. I'm building a power supply for a cnc machine and I need help designing a circuit to power fans when it's over a certain temperature. Here's some things it needs: 1) 12 volts supply (easy with a transformer and filtering it) 2) power fans when it reaches a certain temperature. 3) still keeps the fans on even though the rest of the system is off. 4) after the system if off and it's down to temperature then the transformer turns off, to save electricity and to not make it hot after a long time. If possible can someone draw up a schematic? Thanks in advance!

Topic by guyfrom7up   |  last reply

### Send power wirelessly?

Is it possible to send power wirelessly? If it is, could someone tell me how to do it? I want to mod my wirelessly Xbox 360 controller so that it wouldn't need batteries. Thanks

### Computer Power Supply?

Can i use a 20+4 pin power supply on a 24 pin motherboard? THANKZ!!!!

Question by sci4me   |  last reply

Hi Guys! I need some help. I recently got several pc power supplies and I don't know how to turn them on. That sounds stupid, but I don't really work with them much. I tried plugging it in expecting the fan to at least turn on, but nothing happened. No outputs from any of the leads either. What am I doing wrong? Thanks!

Question by transistorguy   |  last reply

### Power Amp Build?

I was wondering if there is anyway to turn a set of old computer speakers (the amp inside the computer speakers more particularly) into a power amp? I know it would be a pretty pathetic power amp but I was wondering how I could do it.

Topic by batboy61490   |  last reply

### Power supply cooling

I'm building a power supply for my cnc machine that gives off about 37volts at 8 amps, and 12 volts at 0.9 amps. All of the transformers are from radioshack (using 6 heavy duty, 25.2volts, 2 amps transformers, 4 in parallel giving off 25.2 vdc at 8 amps, and 2 12.6 volts in parallel. Together in series gives about 37 volts at 8 amps. using 1 25.2 volts 450mA transformer, center tapped) My case does not have enough room for proper cooling such as fans. My case is water tight though, should I fill it up with something like mineral oil to keep the transformers cool?

Topic by guyfrom7up   |  last reply

### power supply help

Hey I need help building a pedal brick power supply like the one here. i could just buy one but it wouldent be as fun, and i would rather build one if any one can help or knows of a schematic with multiple 9 volt outs i would appreciate your help.

Topic by chrischavez   |  last reply

### Powering Peltier Plates

Hey guys,So, I just got a Peltier plate, a device that gets very hot on one side while very cold on the other. It requires 90 watts of power. I was just curious what would happen if you powered it by USB or 9v battery. I found this tutorial which uses USB, however, I doubt it gets to its maximum coolness potential. Also, if I used a 9v, would that drain the battery in a matter of minutes, or even damage the plate?Thank you.

Topic by Joe426   |  last reply

### simple power supply

I have a project that needs a 24VDC input, at only about 300 mA. I don't have any 24V power supplies, wall warts or anything else lying around, but what I do have is a 120 in, 24 out transformer, a bridge rectifier, and a large cap. Is there any reason why I shouldn't just use those? I'll put a fuse on it. I have some 317 voltage regulators but they dissipate too much to provide the full 24V. 317s are short-protected and the like, which obviously my little kludge wouldn't be, but beyond that, is it a bad idea? thanks,

### Bicycle-generated Power

I want to make an attachment for my bike that generates and stores power when I ride it. I'm thinking of using and old car's alternator, but I don't know much about electricity, so I'm asking for help. Also, how can I store the power? In a battery? I'm planning on hooking up a plug outlet, which might be removable to save space. Thanks!

Topic by jaredsalzano   |  last reply

I have a sima 140 Watt power inverter, and it doesn't work anymore! I don't know why... I don't have much experience with inverters. Can someone help?

Question by martzsam   |  last reply

### Power for 2 motors

Hello everyone, my question is regarding power supply for an Arduino UNO with an Adafruit Motor Shield. I want to use 2 motors that are 12V(link below). I know that the power supply needed should be about 1v more than that of the motor, bu if I want to use 2 motors, do I need to double the voltage of the battery? motor: http://www.abra-electronics.com/products/29DM12V-Single-Shaft-6V%252d12V-DC-Motor.html

Topic by vek11   |  last reply

### Power the Arduino alone

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

Topic by vek11   |  last reply

### Power bypass circuit?

Hey everybody, Ok so here's the deal...I'm building some external speakers for my zune. I'm using some the board out of some old computer speakers to amplify the sound. Right now, since I'd like to make it portable, I've got it hooked up to a 12v regulator going to two 9v batteries. Since it seems to drain the batteries of charge pretty quickly, I'd really like a better way to keep them powered when I'm near a wall outlet (like when I'm at home). I managed to find an old 12v wall adapter that I could use as a constant source of power. Correct me if I'm wrong but I'm pretty sure that I can't have it and the batteries hooked up at the same time. So what I'd like to know is how do you build a bypass circuit (or whatever it's called) so that, when the wall adapter is plugged in, the board will draw power from it instead of the batteries? Sorry for the long read, and happy building everyone.

### Flash Power Supplies

I don't have a lot of money to spend on stuff at the moment. What I do have is flash guns. Four of them in fact, three of which can be fired with triggers. Now I could invest in 16 rechargeable batteries. Or should that be 32 in case I run out? And a crap load of chargers.  And extensions cos we have no spare sockets in our house. But that just doesn't seem right to me.   Heres what I propose : 1) make some dummy batteries from wood with wire running through the middle.   Three of these go in each flash to carry the connections  2) a fourth dummy battery carries wires out of a small notch in the battery flap door 3) said wires are connected in parallel to a large rechargeable battery - I reckon a 6v from an old British motorcycle (fast draining) or from a granny wagon (deep cycle) should do the trick.  4) when I'm done shooting I charge this single battery from the mains charger I have (does 6/12v) I figure 4xAA batteries at 1.5v = a 6v battery, bu extra size should last longer, be more convenient than carrying around dozens of AAs and changing them and if I want to use AAs when our and about I still can   Any reasons tho wouldn't work or I shouldn't do it?

Topic by ohowson   |  last reply

So, I'm doing a project that needs to boil maybe 8-10 drops of water very quickly. I was thinking of using NiChrome wire to do this as in the included diagram (sorry low quality, MS Paint). However, I can't seem to find an appropriate power source. So, I need some easy to obtain powersource that is also relatively small. Something like batteries, a capacitor bank, or anything similar. Remember, it has to be able to boil of those 8 drops pretty fast, lest they condense in another part of the pipe before the desired pressure is reached.

Question by LiquidLightning   |  last reply

### Solar - Powered Batteries

Check out these cool batteries! Their creator is Knut Karlsen.See what he said:At home i always have some batteries lying around, either rechargeable or normal ones. Usually they are empty, but i'd like them to be always fully charged. I could use a normal charger and there is a lot of solar devices that charge rechargeable batteries. I wanted it simpler; why hasn't anyone made a battery with integrated solar cells? The idea of the "SunCat" batteries where born. The batteries should just bask in the sun like a cat and left for a while, in a sunny window, they would slowly recharge.For more details visit this site.Thanks!Stanislav

Topic by comodore   |  last reply

### Raspberry PI power?

Hey yall! I just recently bought a Raspberry Pi! Those of you who want to order know how hard this is, so Im pretty excited because i didnt think Id b able to order for awhile. Anywho, I wnat to make or buy a portable power supply for it, but I am not sure how to go about doing that. I know there are tons of portable CHARGERS out there for iphones and what not, but I am afriad these will attempt to "charge" my PI, therfore frying the board. Do they just supply power and the device recognizes power being recieved, so it displays charging? And I will be attachin a BUNCH of things via a usb hub to the Pi, so I doubt regular bunch of 4 rechargeable AAs will pwer my device for long with all thse extrra things drawing power. So my question is 3fold: can I buy one of those portable chargers to power my Pi or will it fry it? will 4 AAs be enough to power the Pi and all the extra usb things? and will it be more cost efficient to make a power supply? (I definetely want it be rechargeable, though). Any links to products, or guides to make one would be extremely helpful. Thanks in advance!!! Also, I already have a wall supply, but I need a power supply that is portable.

### Can a power adapter be built with batteries and a 110 power converter to power a battery powered flash or camcorder?

The idea is to take 4 AA 1.5 volt batteries that power the flash and wire them together. Then wire the 4 AA's to a 6 volt power adapter so I can plug it in to 110 volt out let. Thus making my flash hard wired.

Question by dgimeson   |  last reply

### Battery Powered Lightbulb

Is it possible to power a household size incandescent lightbulb with a battery? If so how?

Question by DELETED_MakerNinja   |  last reply