designing and building power supply using pre amplifier and darlington transistors

am doing a project on building a power amplifier driven by a pre amplifier with normal darlington complementary power transistors for school and i have no idea of where to start with.HELP PLEASE sandra

Posted by sandy23 7 years ago


Need pre wired high power leds

I am in need of a pre wired High Power Led board. Something like a Cree XR-E Q2 Emitter. I would like to find a supplier that I could buy pre built/ wired boards (plug and play) to install in a small lighting package. Ideally I would like to find a pre built light that I could incorporate into my project. I need a high output 12v white light, that I can make a reverse light out of. I am hoping to market the product so a supplier over a retail option would be best. Any help you could give would be greatly appreciated Thanks in advance  

Posted by returnforservice 7 years ago


Pre-peeled versus fresh garlic?

In what dishes can you tell the difference between pre-peeled and fresh garlic. How about Chinese versus Californian pre-peeled garlic?If you can tell the difference, how can you be sure? I love garlic, and use a lot of it. I'll toss a handful of chopped cloves into almost any savory dish that involves a sauteing step. Using so much and being pressed for time, I primarily buy Californian pre-peeled garlic, and chop it right before I use it. I'm curious if you judge pre-peeled garlic to be less flavorful, and if so, can that flavor be returned by an increase in total garlic or if there are fleeting compounds that escape as soon as the garlic is peeled.Another thing I've noticed is that I need to be careful when I make dishes where I food-process the garlic to mince it. I've ruined a curry or two by using food-processed fresh turmeric, fresh peppers, and pre-peeled garlic that smelled fine but had probably spent a week in the fridge. In the finished dish, the garlic contributed a pretty nasty "raw vegetal" taste. Similarly, Christy once food-processed and sauteed some onions and older pre-peeled garlic only to have the whole mixture turn blue and taste horrible. http://whatscookingamerica.net/Q-A/bluegarlic.htmThe discoloration is due to pigments that form between sulfur compounds in garlic and amino acids. When the garlic tissue is disrupted, as happens in processing, an enzyme is liberated and reacts with it to form thiosulfinates compounds that then react with the natural amino acids in the garlic to form blue pigments. The age of garlic determines how much isoalliin there is in the first place, and the nature of the processing determines how much enzyme is liberated.The blue color apparently shouldn't harm the taste, so it would be neat to develop a dish that naturally turned blue using this reaction while still tasting great.

Posted by ewilhelm 9 years ago


Is it possible to create a pdf of draft Instructable, prior to publishing?

Hello - Another group is reviewing my Instructable prior to publishing.  I sought their permission to use some of their reference material.  They have asked if they could review the Instructable in a pdf format.  It seems like you can only produce a pdf after it is published.  Is there are pre-publishing method?  Thanks, dorybob

Posted by dorybob 5 years ago


help to remember what im doing

The pic says it all lol. i can remember for the life of me where i am to solder the bass pickups to and where the out put goes to lol. ANY HELP PLEASE *begs on floor kissing feet*

Posted by joypad 5 years ago


Well Filter

Hi there, I need a water filter for my well, which i can hook up before the water riches the pressure tank. I got a lot sediment in the well. I was thinking of a filter like from a fish tank. My Idea is , i fill it with gravel from big to fein (Sand) gravel in at least a 6 inch pipe and about 4 feet long. The pump company ( Flotec) told me that i need a pipe with min. 100psi rating. I want use a clear pipe so i can see when i have to change (clean) the gravel.It should also be mounted in the basement ( freeze protection). I found on the i-net a clear pipe with treats on the top and bottom, but than it's not rated any more for 100 psi. so what can i do. Any clue?

Posted by germanudo 10 years ago


Want to know how to build a waste oil pre-heater for a waste oil burning furnace.

Who out there can tell me how to build an oil pre-heater for a waste oil burning furnace. I need to heat the oil so that it will atomize through a Carlyle AF 15 oil burner. Any help would be appreciated.

Posted by rattle09 9 years ago


Gameboy Mintyboost Solar ???? You tell me

First off, I'm a noob, but so far I have learned a lot. I have made the mintyboost with the solar ipod charger mod, but I had to put it in something different that a mint can. So naturally I went back to my roots and thought of the old school gameboy. So my ??? for you the educated and creative community is what else can I put in this case for fun?  On the front are 8 possible switches I could use to turn on/off led lights, mp3player, spy camera, taser, simon says, etc I just wanted your ideas on what you would put in. Thanks!

Posted by 007onionrings 8 years ago


Pre-Formatted Text Issues

Hello; Several of our instructables have pre-formatted text in them. However recently this text has stopped displayed properly. It has gone from being multiple lines to a single long line. Is this a fixable issue? Examples: https://www.instructables.com/id/S99CDK8FWS6JUQS/ https://www.instructables.com/id/SAXXIILFSH7EDVM/ The Long line after "The Code"

Posted by oomlout 8 years ago


What do i need to do 2 be a pre member?

What do i have 2 do 4 a pro membership? is it free? What does it do?

Posted by hobo8675309 9 years ago


Buy or Build a PC?

I'm having some trouble deciding whether to buy a bare bone kit computer for less and build it, or buy a more expensive pre-built one.Here's one of TigerDirect's bare bone kits-http://www.tigerdirect.com/applications/searchtools/item-details.asp?EdpNo=3825393I like this one but the main problem is that I'm worried i will get all the connections messed up (serial cables, pin connectors, etc.) But it is about $100 less than this pre-built one belowhttp://www.bestbuy.com/site/olspage.jsp?skuId=8885575&type;=product&id;=1212192194316So here's the whole thing in short- the bare bone kit computer i might screw up, but it is a lot less than a pre-built one (I'll probably trust the pre-built one more).Please help me decide which one.

Posted by Caveman477 10 years ago


Whay arent yo watching the Superbowl, pre game, and hype?

 I can't stand football. I'd much rather be here, with the exception of the commercials, of course. So, as I hear the hype, pre game, and other nonsense going on in the back ground, I'd rather surf around and goof on the computer.   What about you?  Feel free to post any nonsense or general gripes on the sport. Such as: Its a brutal sport that people get paid to risk mind, body, and spirit on with little other than monetary gain and a brief shot at fame.

Posted by onrust 5 years ago


How to replace mini microphone with more sensitive mic?

Hi I am trying to replace mini microphone (is very similar to mobile phone microphone) of Audio bug with more sensitive Standard electret microphone with intention that it pickup sound from more than 1 metre distance, and in doing so I am getting too much noise in Audio bug out-put. Do I need pre-amp? Is there any better way to do it? If pre-amp then how to harmonise out put of pre-amp to the input of audio bug? Any help..... Thank you.

Posted by ksaus 7 years ago


How to replace mini microphone with more sensitive mic?

Hi I am trying to replace mini microphone (is very similar to mobile phone microphone) of Audio bug with more sensitive Standard electret microphone with intention that it pickup sound from more than 1 metre distance, and in doing so I am getting too much noise in Audio bug out-put. Do I need pre-amp? Is there any better way to do it? If pre-amp then how to harmonise out put of pre-amp to the input of audio bug? Any help..... Thank you.

Posted by ksaus 7 years ago


Find 3D components for Eagle/POVRay

(Where) can I find pre-made libraries of Eagle components for the POVRay? Thanks

Posted by perkinsb1024 10 years ago


Iceblast! aka best fizzy slushy

Hi, i was wondering if anyone could help me. I have decided that as much as I love Iceblast (tango) that you get at the cinema, I can't keep buying them. So I have decided to venture into the  world of indistructables. The way I see it, it should be possible to recreate the conditions of a slushy machine with the following: Freezer A Motor A mixing stick a bottle to contain the pre-slush pre-slush(for testing will be juice) Basicly the motor will poke through the bottle lid stiring the pre-slush as it freezes. Can anyone offer any advice, precations or adjustments? thanks. :D

Posted by balmut 8 years ago


Looking for pre-printed circuit boards

I've been looking around the web trying to find a place that sells ready made circuit boards, plated and pre-drilled; like what you would find in Radio Shack but with a larger selection. I've looked at Mouser and their selection is rather limited. What I need is a circuit board about 1" square for mounting tactile buttons on it.  Like I said I've been looking all over and all I can find are websites that make custom circuit boards, but nothing already made. So anyone know of a place where I can buy already made circuit boards?

Posted by wickednick 5 years ago


old coins

Anyone have any old coins sitting around(or collections) pre 1950 foreign and us? looking to buy.

Posted by drewscollectibles 4 years ago


Larger K-nex like parts for pre-K

I just discovered that the K-nex like building set I have isn't K-nex!  The pieces I have are larger and are made of a softer material.  They work well for children in the 2-5 yo range.  Would anyone know what these pieces are called?   The 1000 pieces of K-nex are going to have to wait a few years..... Thank you in advance.

Posted by brainfog 1 year ago


Preview opinions of the new show: Warehouse 13 ?

Does anyone have any pre-July 7th (premier time) opinions of the new Sci-Fi show: Warehourse 13 ?

Posted by Goodhart 9 years ago


Source for sheared flush circuit boards

Thinking about making wallets and or clipboards with circuit boards for the holidays. Does anyone have a source for sheared flush (pre soldered) circuit boards? Any help is greatly appreciated 

Posted by lepow 6 years ago


Source for sheared flush circuit boards

Thinking about making wallets and or clipboards with circuit boards for the holidays. Does anyone have a source for sheared flush (pre soldered) circuit boards? Any help is greatly appreciated

Posted by lepow 6 years ago


Call for pre-made parts!

We're rolling out some new parts for the Kits in 123D Design.  That means you'll soon have some real-world models at your disposal in the Design app, and I wanted to see if there were some specific requests out there for parts that you might use on the regular. I've put in for some tools and hardware - like metric and SAE wrenches and hex bolts - but is there anything that you'd like to see as a part or a template?   M4 screws for an Arduino enclosure? 4" 2-way gate hinges? Eye-Hooks? Light bulbs? Threaded rod? Phone cases?

Posted by andrewt 5 years ago


I need help on how to connect the components together on an ic board

I need to know how to solder the leads of one components to the legs of another one(the Perf Board doesn't have pre-connected copper tracks)

Posted by wesie42 10 years ago


Cannot access pre-existing "non-pro" topic (and captcha not required for PM)

Part 1:I can no longer access this topic:https://www.instructables.com/community/Could-this-be-used-as-a-guitar-amp-or-converted-in/...which I had replied to earlier. It was created by jackillac92 a day or two ago.When clicking on the above URL, it's redirected to:https://www.instructables.com/account/gopro?nxtPgName=/community/Could-this-be-used-as-a-guitar-amp-or-converted-in/&nxtPg;=/community/Could-this-be-used-as-a-guitar-amp-or-converted-in/Part 2:When I sent a PM to jackillac92 to notify him that I could see his msgs but not respond, I was NOT sent through the usual captcha hoop before the msg was sent.

Posted by gmoon 9 years ago


Best of Instructables - Magnetic Fridge Lights Preview

Check out this Best of Instructables Book preview of the Magnetic Refrigerator Lights.Are you ready for 100 more like this? I am.See the latest news about The Best of Instructables Volume 1 here.

Posted by ewilhelm 9 years ago


Instructables' Annual Pre-Maker Faire Ice Cream Social!

It's that time of year again! In the spirit of Maker Faire and all things DIY, Instructables is hosting our annual Pre-Maker Faire Ice Cream Social - and you're invited! We want to thank our awesome community of authors for sharing all the cool stuff they're making, and for helping us grow our site to 75k projects! We will be hosting this free ice cream social at our downtown San Francisco headquarters for all our authors and maker friends. Come meet the team behind Instructables and get an inside peek at our lab. In addition to some frozen Liquid Nitrogen ice cream treats and adult-beverage popsicles, we will be holding a "Show & Tell." Bring along a small project of yours to show off! And, just in case you're not already going, we'll be raffling off a select number of tickets to the Bay Area Maker Faire. So please come join us! RSVP in the comments below When: Thursday, May 17 4-9 pm Where: 82 2nd Street, San Francisco Looking forward to meeting you, Karen and the rest of the Instructables Team

Posted by kazmataz 6 years ago


The Buccaneer 3D Printer

I just stumbled upon this while looking through kickstarter. It's called the Buccaneer, it will retail for ~$350 and you can pre-order it in August. From what I've read it will ship late this year, or early next year. Check it out on their Kickstarter page or their website.

Posted by Xthinker 5 years ago


Pre-historic Video Amplifier Antennas useless?!

I've been learning quite a bit about video amplifiers recently. And it's brought me to a question. When antennas were the source of video-signal, you would often hear horror stories of people having to get up off of their couch to adjust the "bunny ears", to get a clearer signal. I'm just confused. Why would they have to be adjusted? The signals, if my understanding is correct, is electrical signals sent through the air, and the signal would cover thousands of feet. It surely didn't matter if the antenna was all but a few inches from one spot or another. The signal should be able to hit it just the same no matter what, correct? If you are in a car, it's one thing - you're moving. But in a house, you're stationary. Any explanation?

Posted by freethetech 6 years ago


Advice; How to convert a smoke detector to use a recorded message

Hi, First post...be gentle! Trying to find someone to guide me through converting a normal, off the shelf, home smoke detector so that it emits a pre-recorded message, rather than the usual siren. Anyone? Thanks Naldo

Posted by naldo58 2 years ago


RFID query: Programming RFID lock to accept "pre-existing" RFID chips?

I have no prior programming skills, and only a basic understanding of RFID technology. As my initiation to Arduino programming, I would like to build an RFID door lock/catch. I know you can buy RFID tags to program the system to accept, but can you also program the reader to accept other items you may have with an RFID chip? I'm not sure what other components might be in place to prevent that from functioning. Disney has RFID chip embedded bracelets, for instance which are used for a variety of things around the park.  They way I imagine the programming is that the reader reads an RFID and then records that ID to accept? Is there much more to that? Apologies for my ignorance at this point. Thanks to anyone for their clarification!

Posted by davidandora 4 years ago


Reindeer Ride Paper Animation

Reindeer Ride is my latest downloadable paper animation kit. I've made it available in two flavours. There's a free uncoloured version for you to colour in and for a modest fee a pre coloured version. Both feature the same animated paper reindeer. There's a YouTube link here.Hope you enjoy it!Rob

Posted by robives 8 years ago


It's safe to wear light-up sweatshirts in Boston again - or is it?

Star Simpson, everybody's favorite LED-bedecked MIT student, got pre-trial probation today after Suffolk County prosecutors acknowledged they didn't have enough evidence to actually charge her with a felony.(but read on ...)http://www.universalhub.com/node/14827

Posted by OldProfessorBear 10 years ago


latch with timed variable reset using transistors

I made a 555 t flip flop and it works nice (i use it as a light switch in my room), but i would like to add another button, whet i pres it would turn the light on  for a time and then automatically off after some seconds to minute. can anyone help me?

Posted by bugijs123 6 years ago


Lipsynching talking head

Hi, can anyone help me ? I need to put a mechanism into a latex puppet head to allow it to 'speak' and lip synch while I either operate it ie 'I speak - it speaks' or so that it can tell pre recorded stories. Can anyone please tell me how I can do this ? Thanks jeff

Posted by jeffwoods 10 years ago


The new solution for airport security troubles!!!!!!!!!!!!!!!!!!

So i saw this ad on ibles and guess what?it's what i was talking about in my other forum about airport security!!!!!!!!!!!!!!!!!you can get pre-screened to pass through the hassle we know as airport security!!!!!!!!no more long lines!!!!!!!!this very extremely wonderful thing

Posted by AnarchistAsian 9 years ago


DIY flashing shoe sensor

I've seen tons of guides on how to make my shoes light up with the guts of an old pair of light up shoes, but I dont want to go out and find an old pair.  Does anyone know what kind of sensor they use to turn on the lights and any pre existing circuits I can use? 

Posted by rpeet687 7 years ago


DIY Car Carpet?

Hey, I have a 2000 Toyota Echo with holes in the carpet I've done a fair amount of searching, but I can't find an aftermarket manufacturer that sells pre-molded carpets for this car. Has anyone experience in replacing their car carpet with a custom carpet? How do you compensate for the lack of molding? Thanks, kd.

Posted by killerdark 7 years ago


area 51

Can anyone prove or disprove that this is actually area 51? at some time pres. clinton gave that branch permission to deny it's existence. you used to be able to see it from a hill or something, but they fenced it off and may have cameras there here's the link to the image: http://tinypic.com/k9zvaw.jpg, if that doesn't show up just go to google images and search for "arial view of area 51"

Posted by Pumpkin$ 10 years ago


Cheap IR illuminator

I have been wanting to make night vision for a while and I get the question. How do I make an IR illuminator? Well I can buy 15 long range IR LEDS or I could buy a pre-built one for under $20. I have searched everywhere and still can't find what i'm looking for.

Posted by ry25920 10 years ago


PLEASE HELP!! (sonic grenade)

I'm trying to make an insanely powerful, directional sonic grenade. all I need to know, is how in the world to get something smaller than my fist to put out between 300 and 600 DB however, there is a small catch. I want it to put out a pre-recorded sound that I designate. not just a random beeping.

Posted by James (pseudo-geek) 10 years ago


motion sensor that activates a recording!!!!!

Hi I was wondering if anyone could tell me how to build a motion sensor that activates a recording. It would have to be a small unit no more than 3-5 inches. what I would like to build is that when a pereson walks by the unit they activate the sensor and a recording(that has been pre recorded) is played. Any ideas on how to do this??????

Posted by shilos 10 years ago


BF3 and MW3

Are you going to buy Call of Duty: Modern Warfare 3 or Battlefield 3 or even both? If so, on PC, XboX360 or PS3? I already have the Battlefield 3 Beta for PlayStation 3 and I think it's awesome. I pre-ordered MW3 for Playstation 3 for only 16 euros. Guess how that's possible. Greetings, H.

Posted by H1T4TCH1 6 years ago


My newest gun

This is my final version of this gun. It was originally called an M16 but it doesn't look like one anymore. There are removable clips that you can pre-load, the front grip is detachable as is the top sight rail. I'm posting it on KI at the end of the month. Instructions have been posted http://knexinnovation.gigacities.net/forum/viewtopic.php?t=199 http://www.youtube.com/watch?v=qWQf0xlWzfg

Posted by bakenbitz 10 years ago


Best Way to Mount a NEMA17 Stepper Motor for my CNC

I'm building a CNCrouter, and  I'm wondering if any of you have a specific way to mount NEMA 17 stepper motors that you found to be the most secure and effective? I was thinking of buying a couple of the pre-made metal ones on ebay, but I'm wondering if there is a better diy option.

Posted by MakeItWithJason 5 years ago


how many servos can an arduino control?

Hey, im in need of a little bit of help with the arduino. im new to it and need to know how many servos an arduino can independently control as all the pages ive found seem to indicate 2 but i need 3 servos to run through a pre-programmed set of steps. please help. thanks

Posted by budsiskos 9 years ago


Printing on Bottlecaps?

I'm doing some small scale brewing, and I want to rig up some custom labels & caps for a real professional presentation. Labels are easy enough, but caps are throwing a few spanners into the works... Does anyone have any ideas on how to print them? Here are my current ideas:Toner Transfer - use a custom template and rig to hold multiple caps, then use an iron modified into a solder-press-like device to transfer. removing the paper cleanly could be difficult, and the results are unpredictableSilk Screening - build a similar rig to hold caps in place, and screen them. i don't know much about creating screens, and longevity, but it's probably too complex/expensive for small batches.Custom Stamp - use a rubber or pre-inked stamp to impress the design. simple, but expensive for multiple designs. i don't know how well the ink for pre-inked stamps will bond to metal, and I don't know what ink to use for a rubber stamp.Any thoughts are welcome.

Posted by gschoppe 10 years ago


how to factor a 4 degree polynomial?

How would I solve an equation similar to this purely by using algebra, no graphing as I want exact answers. For those people that don't like helping people on homework, I have to say this. I have like 20 problems like this, and I just want to get down how to solve them.x3 -3x>x2 + 7btw the class is pre-calc

Posted by guyfrom7up 9 years ago


Will "preformatted" text be fixed for existing 'ibles?

Just noticed today that the instances of preformatting I've included in past instructables don't display correctly. The three-bracket "tag" that works like the "pre" tag in HTML... Currently, it changes to a fixed width "courier"-like font, but no returns in the formatting are recognized, so the text just disappears off the right column (and doesn't wrap, either.) Same for old formatting in the 'ible comments, too. No returns in the PDF, either...

Posted by gmoon 8 years ago


USB to ps/2 keyboard adapter

I gather that computers that only have ps/2 sockets (no usb connectors) cannot simply use a basic adapter for plugging in a usb keyboard. I have never tried. Would it be possible to create an adapter to allow a usb keyboard to be used with such a pre-usb computer ? I found one arduino project that converted ps/2 to usb and I imagine that to be more difficult.

Posted by scubascooby 1 year ago