Extracting lead from car batteries?

I have a couple of battered old car batteries. There is no local scrap dealer that will take them so I was wondering if it would be possible to extract the lead myself and sell it for scrap. I have searched on google and cannot find anything about this and I suspect it would be dangerous and impractical. However I thought there's no harm in asking here. I was imagining that I could open the battery up and pour the acid into some kind of strong alkali, neutralising it to make it safe for disposal. But then, I certainly wouldn't like to try this without some advice first. Cheers! Pete

Posted by peater 8 years ago

A couple questions

Hey guys, I want to bug you's again. Instead of trying to ask about different things in one of my other topics, I wanted to start a new one. I went to the local dump today, and one of the first things I spotted was Three, not just one, booster packs. You know, the ones you can charge up and boost a car with, and some of them have inverters built into them so you can run small appliances. Well I snapped all three of them up, thinking that at the very least, the lead acid batteries inside them would be OODLES of help towards making a full scale wind generator (I plan to build one or two full size wind generators with car alternators, whenever the good weather comes and I can work outside). Well, I got them home and cracked them all open. Turns out that only one battery is good to me (pictures below). The two identical units have 350 watt inverters built into them (I've removed one so far), but the batteries were bulging and the sides were split open, although not leaking, which was good, less mess to clean up. The third booster pack I opened appeared to have been already attempted at being opened. 4 of the 6 screws had been drilled out (which is beyond me as far as why they would do it? They were only phillips screws), but maybe they weren't successful? It had a couple wounds of electrical tape around it to hold it together. Needless to say, whatever cutting tool they used, cut into the battery itself (they cut too far in, dumbasses...), and so my main question here is, is the battery safe to charge, and use? I took some macro's of the damage and some of the cut marks seemed to have gone far enough in to cut into what appears to be a white plastic lining inside, as the white crud on the sides of the battery feels more like burnt on plastic from a cutting disc than it does acid that oozed out and dried up, so the damage doesn't appear to be that bad. What's the worst that could happen anyways? Also, the battery has about almost 8v left in it, and another question is, is that too low for a 12v battery? Like has it been discharged too far? Also, aside from the battery. I found this plate with a transformer, giant capacitor, and a pcb that looks like it was some kind of voltage converter board (I would take a picture but I've since cut a few things off of it and I won't even bother now) The transformer puts out 25v and you can see in the pictures what the capacitor is rated for (I would like to know what I can use this capacitor for, or if I should save it and wait till I can make a bank of capacitors for a tesla coil project or something) What I can't figure out, is what is this square device I found that was plugged into one of the output leads of the transformer? It only had two leads coming off of it, one is marked + and one -, the other two terminals don't have marking on it. No model numbers or anything. Does anyone know what this is? Also, last in my pictures is one of the inverter boards I pulled out of one of the power-packs. I cut the second outlet off and wrapped the first one in tape just to make sure I dont' shock the hell out of myself. I have my truck battery sitting inside over the winter, and with a good 12.71v, I thought it would be the perfect battery to try the inverter on. I brushed the wires onto the top terminals of the battery and although I could hear a bit of sparking, I saw nothing and the indicator light on the power switch didn't light. The volt meter also showed nothing from the 120v outlet. So I tried shoving the wires into the bolt sockets that the truck's wires bolt into, and I quite literally startled myself as it emitted a really loud BEEEEEEEEEEP, I nearly jumped through the roof. The indicator light turns on when I flick the switch to I and I can hear the transformer making a little buzzing sound. However, when I measured the AC voltage from the outlet, I didn't write down the voltage, but it was around 3v? Not even quite that much. I'm not sure if the inverter is screwed or if it has something to do with the switching nature of power inverters causing my multi-meter to not read it right? One other thing I will note is that I had to cut the power switch leads to remove it from the case, then re-solder the switch. The switch has 2 black wires and one red, I tried my best to make sure that each black wire went to the terminal on the switch it came from, and I assume if I didn't hook the switch up right, it wouldn't have lighted up or anything right?? I don't want to try plugging something into it for fear that it will blow up in my face, at least not until I know it's functioning like it should be, however I doubt these power packs were throwing out for failure of the inverter... *On the side note* I apologize for these (sometimes) rediculously long posts or just mundane questions. However, I like to be thoughrough with my questions so that there are very little questions asked, about my question, in the first place. As it seems to waste a lot of time asking for details about this or that problem, when you could just throughly explain it all in one go. This is what I try to do, so there are no blank spaces for you guys to try and "assume" where you don't know the proper information. Secondly, I've really appreciated the help, and sometimes just the helpful and creative ideas I hear from others, makes me feel good, like there's actually some people on here that know what they're doing and I can trust their answers (Nacho, kiteman, caitlyn's dad, 1010100100, all of you regulars, have been great help to me) *End of girlish requiem*

Posted by Punkguyta 9 years ago

Electronics dummy needs your input please

Hi, I want to run a battery operated item that takes its power directly from my 50cc mopeds 12v 4ah battery.  The item takes a minimum of 60w and can take upto 100w which I'm told, could drain the mopeds battery too much even when the engine is running at full speed charging the battery. Can I connect an adustable 6-24v step up inverter to the main bikes battery and use it to install and charge a second 12v bike battery purley to power the 60w to 100w electrical item while its in use, saving my main bikes battery to besure it won't run out of enough power to start the moped after Ive finnished using the electrical item? Im sorry but I not good at electonics and need your input to help guide me to run the item from my 50cc scooter/moped.

Posted by selectauto 5 years ago

Request for Toy Lead Test Instructable

There are constant reports of high lead levels in many toys, as well as new findings that lead is an even more dangerous neurotoxin than previously believed. Does anyone have the chemical background to devise a simple home test for lead levels in toys? My thoughts are that a number of toys would be place in a bathtub, and a leeching agent would be added which would dissolve some of any lead present. The dilute solution in the tub would then be tested by a standard home water supply lead test. This could possibly be a great service... Thanks!

Posted by bugmenotorelse 10 years ago

Shattered CRT Safety

I'm thinking of cutting the phosphorecent screen off of a CRT and seeing what effects I can produce by shining some high intensity UV light on it. Removing the screan is going to be tricky since the entire CRT is a vacuum on the inside. I know I'm going to have to be really careful and let the pressure in slowly or it could implode and send shards everywhere, but I'm also worried about what dangerous substances might be in the CRT that I could expose myself to. Does anyone know if there is a danger of lead/mercury/etc on the inside of the CRT, and what safety precaussions I can take?

Posted by kramerr 9 years ago

single lead capacitor

How can i make a single lead capacitor for this https://www.instructables.com/id/DIY-Lightning-Wand-a-Handheld-Van-de-Graaff-Genera/

Posted by taterkiller 8 years ago

Lead guitar

Ok, Danny posted his "lead guitar" instructable, and he won't let me edit it, even though i have tried before, so should i make my own????

Posted by Metal4God 10 years ago

Convert Crayons into 2mm+ Leads Like Graphite Lead

Hello! I want to recycle crayons and thought of converting them into 2mm lead or larger in diameter (since there’s only a certain thickness where crayons can be sturdy). I also thought the crayons should be mixed with something since they’re wax. I was thinking of buying a silicone mold rubber to make a mold (may make the lead bend since it’s flexible but easy to remove), a polyurethane mold rubber, or a protruder like the old fashioned way. Silicone mold rubber is expensive ($30+). I originally thought of it as a craft, but it’s too complicated for a craft. Thank you for your time!

Posted by TrixiaL 12 months ago

battery problem

I have a 12 volt 7ah rechargeable lead-calcium battery, but no charger. i want to build a charger, but the diagrams ive found are for lead acid. does anyone have a good circuit for lead calcium battery chargers?

Posted by tech-king 10 years ago

Please help me restore this old Lead acid battery

Hello everyone, I just salvaged a small, 50AH FLA battery from a Tractor. The Battery has seen 2~3 calendar years. It was showing 11.38 Volts sitting on the shelf since 3 months so I thought it was good and I brought it for a bargain. I brought it home and connected it to my Intelligent charger which claims to support (Automatic)- Deep discharge Charging Boost Charging Absorbtion Charge Tricke Charge Equization Charge Automatic Charge Current and voltage regulation with Temperature compensated charging. The charger is currently showing "Boost charge" at about 12 Amperes. Problem is,the Charging voltage seems to Jump from 13.1v all the way to 14.2V (like under 10 sec) I hooked my DMM to the battery terminals which comfirmed the same. Sometimes the voltage also reaches 14.4v and the Charger goes into "Equalization Charge" but falls back to Boost charge at 13.5v or something odd. After 3 days for 'Cycling" I tried a eq charge twice. it seems to be improving. the Battery voltage on charge is still jumping across 13.6v to 14.2v. if I draw a load it goes back to 12.3v. admirably, I connected the Battery to our DC load yesterday night and it ran Led street lights (load 4a ) for 5 hours before I switched it off. 20AH is decent progress for 50ah old Battery right? do you think it's sulpahation that's causing voltage jump? I ran the Battery down to 11.5v yesterday. in the morning with sun up, the Battery is slowly progressing from 12.8v and above... very stably. the charger shows'absorbtion charge' at 8-9 amps. 8 amps are good for 50ah Battery right? else how do we test the ah of Battery?

Posted by bhvm 4 years ago

Global Warming Leading to Possible Beer Shortage

According to Treehugger, a warmer climate is leading to shortages in hops and barley. If all of it keeps going in the same direction, beer will be getting more expensive to make and nobody wants that. Link

Posted by fungus amungus 10 years ago

Basic circuitry help? [not yet resolved]

(I wasn't sure if this should be a comment on the Instructable or not, as it is a bit long, and I have some pictures..) I am following a sound-reactive LE 1.D tutorial and having a bit of trouble. The circuit consists of a SPDT switch, resistor, LED, transistor, and a 3.5mm stereo jack. When I play music using this stereo jack, I get no response from the LED. I'm trying to make something on a breadboard for the first time, so I'm thinking maybe I'm missing something because of that. Here's how the machine is supposed to work: - Positive charge flows to SPDT switch, and if it's in the correct state, continues to the 150 ohm resistor - Anode of LED is connected to the resistor, and the cathode is connected to the "emitter" lead of a TIP31 transistor ("base" is wired to the power bus) - The "collector" lead of the transistor is attached to one of the outputs on the stereo jack - The ground wire on the stereo jack returns to the common lead of the SPDT switch. Perhaps I wired something wrong? I've included pictures if the description is not sufficient. EDIT: I've modified the circuit a bit - maybe I can take pictures / draw a diagram tomorrow. Now, here's how it works: - Positive charge flows from positive side of the power bus to the "base" lead of the transistor - Collector lead of the transistor is connected to the left-channel lead of the stereo jack (also, the ground pin of the stereo jack is connected to the negative side of the power bus) - Emitter lead of the transistor is connected to a 150-ohm resistor - Resistor is connected in series with two LEDs - The cathode lead of the second LED returns to the negative lead of the power bus The LEDs do turn on now, but that's the problem - they are always at full brightness no matter the volume of the music. Even if no music is playing, the LEDs are fully lit. I've used a multimeter to check what's happening, and after pressing the negative lead of the multimeter to the cathode lead, and the positive lead to the anode lead, it shows a constant voltage of 1.986 V. I don't understand how this isn't working - I've verified that the collector lead is correctly connected to the left-channel wire... maybe I should try the right channel? Or a different cable? tl;dr: Rewired and the LEDs are always at full brightness. Transistor doesn't seem to be affecting the emitter output, for some reason..

Posted by hansengel 9 years ago

Need to step down a lead acid battery from 12vdc to 10vdc 350mA

I would like to run a 6pcs 1W white led lights from a lead acid battery. A Single bulb input voltage is 3.2-3.6V & 350ma. I connected every 3 led's in Series (2 Groups) . Can I use 7810 IC or how can I do it. Sir Please send me a diagram . lead acid are in full-charge 14.5v. , in normal 12v, low 10v

Posted by Goldensathiya 4 years ago

Lead Free Solder Recommendations

Hello, I am going to be working on some electronics projects soon and was wondering if anyone had recommendations for lead-free solder. Some completed projects are going to be shipped to the EU, California and New York so I need to start paying attention to RoHS standards. I was hoping to get pointed in some sort of direction to avoid buying a dozen different kinds and figuring it out myself. Any advice would be greatly appreciated. Knowledge regarding previous experience with lead-free solder and electronics would be awesome. Thanks in advance.

Posted by cunnane 10 years ago

Clicking the "Edit" link from an instructable leads to blank page

I have to go to you>instructables>published (or unpublished) and select "edit" there if I wish to edit an instructable of mine FF 3 in Ubuntu.

Posted by Lithium Rain 8 years ago

Cavity mold for aircraft wing

I am using Alibre Pro. I want to make a cavity mold for a airplane wing. The leading edge is straight to a point then curves to the tip. The trailing edge is curved but is not the same as the leading edge. Does anyone have an idea how to do this.

Posted by jimp 11 years ago

Waterproof Leads

Hi guys! So i was done with this instructable: https://www.instructables.com/id/Water-Level-Indicator-with-Alarm/ Everything is working perfectly except for one small problem: our best friend, CORROSION The wires that go into the tank are getting corroded. Its forming greenish layers(i assume copper oxide) and after reduces conductivity and also after a while, it washes away with water. I want to attach a metal, which is more resistant to corrosion, to the wires so that i can seal the wires themselves and only expose the metal leads, and since they conduct electricity, my indicator will work fine. The only problem is : WHICH METAL? I have no idea which metal i should use. Anybody suggest something which is commonly available and resistant towards corrosion? Also, can i use graphite leads, the one they use in pencils? Or will it cause any problems?

Posted by charmquark 5 years ago

Links to groups lead to featured groups

When I click on this group, it leads to a list of featured groups: Pro Knexers https://www.instructables.com/group/https://www.instructables.com/group/proknexers// That also happens with this group: Knex Builders https://www.instructables.com/group/https://www.instructables.com/group/Knex_Builders/ If you click a link above and look up at your address bar on your browser, it's not the same link. There's more groups this happens to. Is this just me? Your help is appreciated. Thanks.

Posted by Shadowman39 8 years ago

I'm looking for a lead free soldering station.

Hey everyone, I'm looking for a lead free soldering station. I have to do some soldering/desoldering at work and I'm having a problem. The solder on the board is too high of a temp for my trusty Radio Shack soldering iron. To date I've purchased a 50watt iron and I would say that almost did the trick. But, desoldering was a fail. So, I would like to get a professional strength iron that can do the work without breaking my budget ($120). At this point I don't know what to look at 60 or 70 watt or 80. So, if anyone can recommend a good digital lead free solder station? Thanks Everyone!

Posted by ChrisMc74 4 years ago


Why is it that when i want to follow somebody, it leads to this page: https://www.instructables.com/contest/

Posted by ~KGB~ 7 years ago

lithium vs lead acid for gokarts

For electric go karts, which one is better (for the money)? Lead acid is by far much much cheaper, but it is much much heavier. With a heavier battery you need a stronger frame, which weighs even more. With all of this weight you need an even stronger motor to push it all. With lithium you can build a lighter, cheaper frame, and power it with a weaker and cheaper motor and still obtain the same speeds. Lead Acid batteries take up about 1/3 the weight of a gokart with rider (1/3 being the driver, and the other third being chasis and motor and such). Reducing the weight by about a third (honestly, lithium, batteries weigh like nothing) could have huge performance improvements. So, does spending more money on batteries, and saving money on chasis and motor equal out to spending less on batteries and more on chasis and motor?

Posted by guyfrom7up 9 years ago

3 pronged LED

I just bought some bipolar LED's from a local store. When I opened the bag, I realized that each LED had 3 prongs instead of the usual 2 prongs. How do I use it? Is the middle prong the positive or negative side?

Posted by allstarn07 10 years ago


I would like a LED light which will change tube light. Please lead to me how to do?

Posted by trandung 11 years ago

Torque to linear thrust through lead screw

Hi,I am trying to figure out maximum linear force I can produce with an electric motor through use of lead screw and nut. I have come up with an equation which seems correct but resulting forces are way higher than my intuition believes is correct.I tackled the problem from the perspective of energies:F' * p = M/r * 2*π*rlinear force * thread pitch = torque / radius [M/r = force at radius] * circumference of lead screwF = 2*π*M/p * (1-k) //k stands for coefficient of friction between lead screw and nut)Radius falls out of equation, which seems fine as force is provided by torque, which is radius agnostic. I used a 7€ stepper for source of torque which can provide 0.42 Nm of torque and a lead screw with 8 mm pitch and 4 mm radius, I assumed 15% losses. My equation tells me that such system can provide 280 N of force, which seems wayyy too much for a cheap motor.I have attached a python code that calculates linear force in case it helpsCan someone tell me if my equation is either correct or flawed?

Posted by ptkrf 15 days ago

ECG circuit help

I have this circuit for recording 12-lead ecg in arduino. Whenever I record the augmented leads, especially aVR, its output graph is upright instead of the normal aVR which is downward. I also followed Wilson's Central Terminal but still the same. I am currently stuck with this and I need some help.

Posted by OppaC 3 years ago

Arduino Input

I am writing an Arduino program to read speaker inputs for a test station.  I need only to know when a speaker lead is on or off. This will be done by using the fade and balance.  Originally I was connecting the speaker leads to the analog inputs and could get a single line to work as a simple VU meter. Multiple lines gave issue.  Since I don't need to know the actual level, just whether they are on or off I'd like the speaker lead to trigger a transistor connected to a digital I/O pin on the Arduino.  Any thoughts or quick schematics on how to do this? 

Posted by dbirky 4 years ago

Guide link doesn't work

Clicking on the "Guide" icon leads to a dead link.

Posted by threeDwag 6 years ago

Bismuth suppliers.

I need Bismuth metal to make my own Bismuth Crystals. I cannot locate it at all in Australia Ive looked at the obvious such as metal suppliers etc. even non-lead shot and fishing sinkers but can't find it. I realise that I can buy it online but it is a fairly heavy metal and with the added cost of mailing  to Melbourne Australia makes it very expensive. As I'm going to melt it do you know of any other tools or items made of Bismuth that I could use? Any words of wisdom would help. Thanks in anticipation..

Posted by craftyv 4 years ago


Hey, lead ninja here! Please start adding instructables, we need them to promote our group!

Posted by gen.badger 10 years ago

Anybody tried to dismount sealed lead acid batteries?

Hi My battery started to leak between bottom base and top cover (check pic). Just wondering anybody removed top cover? I know, you can remove top plate in order to add ionising water etc, but the actual top base? Thanks

Posted by Extasy 7 years ago

Doors and WIndows Automation

Hello, I am trying to automate the windows and doors in our barn using NEMA  stepper motor and Lead screw and would like to exert around 20 Kg force for opening or closing. The windows are fairly old and made of wrought Iron. I am wondering if somebody can advise and help me selecting the motor (based on torque) and the appropriate diameter of the Lead screw for this instance.  The idea being that when the lead screw rotates, the ball nut flange moves left or right and pushes the connecting rod out or in thus opening or closing the window I have attached a rough sketch what I had in mind and please pardon me for any mistakes. Many Thanks Ash

Posted by AshishJ61 1 year ago

Fixing my headphones - can't identify the leads

I am trying to fix my headphones - the connection to the jack got a little damaged from using it over time. so i cut the existing jack off of the cable. the cable is stranded wire, so i'm having an awful time identifying which is left, right and ground. i will try to post a picture soon. 

Posted by mrtunes 6 years ago

deep cycle batteries

Can we and how do we convert a normal lead acid battery into a deep cycle battery?

Posted by sankyc 10 years ago

How Many Hours a Day do you Spend on Instructables

I was just wondering how many hours of your day youspend on instructables. I know I spend 6 hours of my day on instructables, and if I find a good instructable, that leads me to more great instructables which can lead me up to 7 or 8 hours a day.

Posted by Robot Lover 8 years ago

Instructable update leading to error

Hi there, I wanted to update my photo Instructable ( https://www.instructables.com/id/Laser-cut-wooden-herborium/ ) but even if I tried yesterday and today, it leads to this error: ERROR 401: edit object EP37PU4H5Y9VOAC - ERROR 401: edit object EP37PU4H5Y9VOAC I wanted to update the keywords, once it's already published (add keyword). The path I followed to get there : - From the Instructable page https://www.instructables.com/id/Laser-cut-wooden-herborium/ - I chose Edit (the buttonon the right from "Author options") - I clicked on the "Publish" tab - I changed the keywords - I clicked on "Save changes" (bottom) - I got the above error. Thanks for your help!     Raphael

Posted by r4f 6 years ago


The Electronic Goldmine  has a rare to find component. "Tiny audio optocoupler is about the size of a pencil eraser and has 4 leads. These are used extensively in audio compressors, audio level controls, audio limiters, expanders/noise gates, guitar tremolo effects, guitar amplifiers and music effect boxes. Inside the black epoxy case is a 2 lead photocell (not a photodiode or photo-transistor) and a 2 lead LED. This is why the device finds extensive use in audio applications (photocell instead of photodiode). The LED requires about 10-16mA current and the resistance of the photocell varies from 150K up to megohms when the LED is off to under 400ohms when the LED is on." A

Posted by iceng 4 years ago

Shorten the lead on a light fitting.

I bought this ceiling light: http://www.diy.com/departments/colours-cantemir-ceiling-light/234751_BQ.prd As you can see from the picture, it seems to fit fairly snug to the ceiling. However, when I got it home I found that the cable length was slightly more than a metre! I mean, who has ceilings that high? Anyway, I thought it would be no problem just to cut the cable down and refit it into the ceiling rose. My wife pointed out that the instructions say, "Caution! The length of the cable cannot be altered." The fitting has 4 x led bulbs. Can anyone tell me if there could be a problem if I shorten the lead? Frankly, otherwise I will take it back for a refund.

Posted by Pateesh 3 years ago

12V LED to Battery Power?

Hello! I'm just getting my own cab company started in my medium sized town, and to begin I'll be using my personal vehicle - thus, I'm using items I can remove so I don't get harrassed on my days off, such as magnetic decals and a magnetic top light. My question is this: Is there a way to convert a 12V, 96 LED light over to battery power? The toppers use a direct cable to a car charger port, but I hate having that cord just hanging out in my cab. It is tacky and unprofessional - at the same time, I very much do not want to punch holes in the top of my car and wire it to my dome light. I have found several rechargeable, compact 12V batteries online, but I've no idea how I'd hook them up. I'm smart enough to know that I can't just wire it directly to the device - the battery would last minutes at most. I think I'd need some kind of transformer, perhaps? Any suggestions? And here's the battery I would use: Voltage: 12 Lead Acid Type: General Purpose Capacity: .8AH Chemistry: Lead Acid Lead Acid Design: AGM Product Category: Sealed Lead Acid Terminal Type: WL, Wire Leads Weight: 0.8 lbs Length: 3.78 in Width: 0.98 in Height: 2.4 in

Posted by NiteRide 1 year ago

USB Flash Drive Tester

I am looking for a tester to use to test USB Flash Drives.  I found a cool USB port tester on instructables, but I need something that would test the hardware functionality of a USB Flash Drive not the USB port.  I am not sure if I am saying this correctly, but reading about the functionality of USB Flash Drives, it appears to be a fuse on the circuit board.  I don't know if all drives have one.  Many of the videos I watched on YouTube require taking apart the drive and jumping the fuse to see if this is the problem.  I thought if there was a way to test to see if the circuit (I am not sure if I am describing this correctly.)  was completing then it would not initially require someone to take it apart.   Looking into this a little further, I see there are four leads on a USB.  It looks like from what I read that lead 1 [+5 VDC] and lead 4 [ground]. Are these the two leads which should show a completed circuit via a tester?  You probably have already figured out by now that I have no knowledge of electronics. Thanks for your help.

Posted by epodowski 5 years ago

Computer Reuse in Minneapolis

Anyone in the Minneapolis area doing cool things with computer reuse or know of anyone who does? Any leads would be appreciate.

Posted by randofo 8 years ago

3D Design

Just wondering if anyone happens to have any good leads to the best free 3D design software?

Posted by marcusmckee33 6 years ago

Ender's Game being turned into... a game.

Ender's Game is being adapted into a video game. It won't be the whole book so no hacking mini-games where you try and post comments as another student. No, this will be focusing on the Battle Room. Even more intriguing, to me at least, is that this will be distributed via Xbox Live Marketplace and the PlayStation Network and not on a disc. Very interesting.So how excited am I about this? Excited enough to say that it will likely be absolutely horrible and worthless. That's right, I'm burying my expectations right next to all those copies of E.T. for the 2600. Otherwise I risk extreme disappointment which leads to rage which leads to fighting words in Internet forums which just leads to a sorry state of being altogether. full story

Posted by fungus amungus 10 years ago

differential amplifier tech

Hello, I'm following a circuit diagram for a current monitor that uses an op-amp as a differential amplifier. Connected to V- and V+ on the amp are the positive and negative leads of a 10mH Inductor that senses the current (as much as 9A) passing through an insulated positive line. The gain on the op amp, I'm told, is 220. If I calculated this correctly then at 9 amps in the insulated wire, 0.09V should be produced by the inductor and there upon entering the V+ lead and -0.09V in the V- lead for a differential of 0.18V which gets amplified to 39.6V. However the voltage source that powers the op amp is only 9V. So question # 1: Did I break down the math correctly? question #2: What happens to the excess voltage from the gain? I am getting all of my op amp information from wikipedia. I've never used an op amp successfully before.

Posted by watchingmachine 11 years ago


From the steam canon to the lead balloon,talk about the gadgets and contraptions the mythbusters built.

Posted by comodore 10 years ago

Mosaics and Lead lighting.

Hi all. I am  a new member with tons of creativity inside me. I create stuff from other peoples junk. For many years I have wanted to turn my hand at Mosaics and Lead Lighting. I want to create a beach scene in Mosaic of Shoalwater Bay/ Penquin Island which is near Rockingham, Western Australia. I already have painted a 16 foot by 7 mural of this idyllic part of the world on my lounge room wall. Looks magnificent. I want the mosaic to be at least 4 feet by 3 feet. How do I stop the mosaic from sliding off the mounting board? Do I drill a myriad of small hole into the board so as to give the medium purchase? Also I want to make Lead Light full window coverings, from 2 feet square up to 4 feet square. Are there any members who would like to give me some clues on how to begin? In researching accessibility of stain glass I have not had a lot of success here in Perth, Australia. Maybe I need to go to junk yards? Thank you for reading my request. Anticipation is high that I will actually begin creating my creations. Bretrick

Posted by bretrick 1 year ago

Location link on profile pages leads to errors.

This bug has been around for a while, so it may have already been mentioned, but when visiting the location link on a user's profile page, you get an error.  See here for error: https://www.instructables.com/tag/type-user/location-iowa/ I know you guys are busy with the site layout re-design, so whenever you get a chance you can check this out (It's not a major bug). Thanks for keeping instructables awesome, Awesome-aniac

Posted by Awesome-aniac 6 years ago

Bow Kite or Inflatable Kite bladder

hello. For the past moth i've been trying to make a inflatable bow kite, all fine till now, i printed out the plans, sewed the parts, but i've stumbled on the bladders, on the leading edge bladder to be more specific. How do i make the bladder when inflated to have the bow shape?i mean how to cut the material and seal it?(the material i use is celofane, cheap and resistent) Thanks.

Posted by rahbert 8 years ago

Bow Kite or Inflatable Kite bladder

hello. For the past moth i've been trying to make a inflatable bow kite, all fine till now, i printed out the plans, sewed the parts, but i've stumbled on the bladders, on the leading edge bladder to be more specific. How do i make  the bladder when inflated to have the bow shape?i mean how to cut the material and seal it?(the material i use is celofane, cheap and resistent) Thanks.

Posted by rahbert 8 years ago

Broken links in Toy Challenge results

Hi there, I noticed that the links for the runner-ups in the Toy Challenge are inaccurate, leading you to the wrong Instructable or to the homepage. Thanks for looking into this Lance

Posted by LanceMakes 6 years ago