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


Anyone know how to build a device that says a pre-recorded message whenever there is power going through it?

Just going to use a simple wall timer so I can make it go off when I want, Im guessing it would just be a recording message device from radio shack and it says the message when you put power into it, does anyone know how to do that. Much appreciated if someone could draw up some schematics for me, Thanks.

Asked by Itscrafty 5 years ago


Do pre-programmed PICs exist?

I'm trying to complete an instructable however I ran across a small problem: I need to program a PIC. Unfortunately, the devices used to program the PICs (Pickit2) are too expensive for something that I'll use maybe once or twice. Is there a way to buy pre-programmed PICs with custom code? Thanks. 

Asked by Rolcrz 6 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


how to stay connected?

My t-mobile acct. has been disconnected.But with my husband in Icu I kinda need my phone.If  I buy a prepaid sim card can I still use my T-mobile phone?Desperate in Fl.

Asked by miamihomegrl 6 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


help! modifications on a vintage pre-amp Answered

I found a working pre-amp inside a turntable from the 60's. The turntable was scrapt, so I remove the pre-amp from inside. Now I want to put it inside a vintage radio wooden box, the problem I got, 5 potentiometers on the pre-amp, but I need to modify this so it will only have 2, becuz the radio box has only 2. I will use an iPad with this pre-amp, so there really no need for extra audio adjustments like treble or bass... So one for volume, the other for open and close. How do I modify the circuit of this pre-amp so there will be no sound problem ? Do I remplace the gradable resistors with a standard value resistor, if this is how to do it, what value should I use ? I've done some tests, if I skip the potentiometer and I'm getting too much static. I' would appreciate help on this! thank everyone !

Asked by sebdub 4 years ago


How do you get a shipping container certified to legally live in?

It would be cool to attach a bunch of those things together and install a bunch of doors, windows, decks, etc. Seattle, Washington

Asked by sensoryhouse 9 years ago


please help me! record player question! need help setting up!

ok i just got a record player,some records, and a pyle p999 phono preamp for christmas. the output is a red and white cord. is there any way to listen to it without getting a amplifier?

Asked by madrobot3600 7 years ago


Arduino LM386 Pre-Amp for Mic ?

I am trying to (pre) amplify the signal from an electret microphone using an LM386. The output goes into the Arduino analog input 5. I have tried multiple circuits, but none of them succeeded. Either the value settles at some constant or its 0/1023 and even when its in the 500- 550 range, the value doesn't seem to be changing with varying sound levels. I tried these circuits: http://wiring.org.co/learning/basics/microphone.html https://randomskk.net/projects/lightstrip/schematic.pdf http://www.josepino.com/circuits/mini_amplifier_lm386 http://www.diyaudio.com/forums/chip-amps/114698-preamp-using-lm386.html and a couple of more ones. I only have an LM386 on hand and cannot change it, as I need this to work out ASAP(in 2 days) for a science fair project. Hope you guys can help me on this. Kabir

Asked by mhkabir 6 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


Good pranks to play while trick or treating?

I need one within three days so I can plan it need some ASAP

Asked by Poprockzftw 5 years ago


pre-school games?

I'm looking for gross-motor games for pre-schoolers?

Asked by 8 years ago




What if my fabric says "do not pre wash"? Answered

Hi! I bought a few fabric quarters from Joanns and the sticker says "do not pre wash," but it has washing instructions. Do I still pre wash it in this situation?

Asked by Stitchtejas 1 year ago


Pre-drilled shelves?

I would like to know where I can purchase the pre-drilled melemine shelving upright boards in order to construct some custom built bookcases.

Asked by masterhog 6 years ago







What are some good arts and crafts for a pre-k class?????

I work with my moms summer pre-k class and i want to know good arts and crafts to do with them somethimg easy and u dont have to spend so much money on any materials.

Asked by EmmettCullenrocks 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 8 years ago




how do i put a verizon pre paid card on my at?

Purchased a prepaid verizon phone card plus want to use it on my at&t go phone

Asked by d1963 8 years ago


How to measure pre-shirred material for a summer dress?

I am new to making clothes and am self taught on my sewing machine. I bought this really cute cherry pre-shirred material, and am trying to figure out how to measure it to fit my body right. Is there a special way I need to do this, or is the answer right under my nose and its passing me by? Any adivce would be greatly appriciate. So, again, my question is, How to I measure the pre-shirred material to make my summer dress?

Asked by 9 years ago


Passive subwoofer and receiver with "subwoofer pre out" plug in harman kardon avr 142

Hello, I have Harman kardon avr 142 with subwoofer pre out plug in (suitable for active sub), and passive pioneer subwoofer with two cords. Between them I have rg59 with rca head (sub cable). Is there a way some how to convert the pioneer sub to an active sub with rca plug in?

Asked by BarD2 1 year ago



Can I make an indestructable based off of a pre-existing one? Answered

If i build something in a different way but take some inspiration and ideas from another creator ( and cite them) is it acceptable to make something already built using different materials or in a different way.

Asked by matosky.caleb 5 months ago




How to pre-record voice module from PC, avoiding using microphone?

Hello. Could anyone advice me, please? I read all of the QA related, but my question would be a bit specific. My intention is to make a greeting card like device, using recordable voice module. Recording your own message by using the microphone is pretty clear. However my concern is, I would like to pre-record this module with any music or jingle from the PC and leave user the option either to record her/his own message using the attached microphone or let that pre-recorded jingle play. I would use any of this type or similar modules shown on picture. Thanks in advance.

Asked by Ardu Tube 6 months ago


any ideas for an old palm pre?

Found one with the orig. packaging about to be tossed.  I figure there must be some good ideas out there; i wanted it originally to be turned into a pay as you go for my kids or as a back up as i crack a few screens.  Any ideas?  Please dont snark.

Asked by GlanternJay 5 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


Find 3D components for Eagle/POVRay

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

Posted by perkinsb1024 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 9 years ago


how to convert from Phantom power 48 to about 9v?

Hi does anybody know how to convert from a phantom power supply +48 to 9v to power a single circuit of a microphone pre-amp like this one "http://circuitdiagram.net/simple-audio-pre-amplifier.html " ?    it is for an electret microphone .... thanks

Asked by maguilar7 6 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 6 years ago


Building a bike light. 12v power source, 12v pre-built led fixture. Need SIMPLE way to make it flash.

I am building a cool bike light (which when finished, will be my first instructable).  I have a 12v power source and a pre-made 12v LED trailer tail light  that I am using for the light element.  What I need is something simple and cheap that I can build or buy to go in between the power and the lights to make it all flash.  Thanks in advance for whatever help that you can provide.

Asked by chrisdoiron 8 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 6 years ago


can I connect pre-kit led strip to a battery wired led strip (see pic)?

Connecting a led kit (white strip) to battery pack (black strip) but am I stripping end both black and white to make it happen. Or way to make black same as white?  Is there an easy way to do this?  Thanks in advance.

Asked by tamsee13 3 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