about capacitors

I understand that capacitors store electricity, but what controls them. what lets them discharge?

Posted by kendallickes 9 years ago  |  last reply 7 years ago


about contests? Answered

Hi i live in lebanon in middle east could i participate in contests or not is there any way to get the prizes?

Asked by buraqo 4 years ago  |  last reply 4 years ago


about heatsinks?

I'm absolutely new to DIY but i've been browsing tinkernut's and kipkay's stuff for a while now. For starters, i'd like to know in general terms- how do i know when to use a heatsink and how to connect to various appliances?

Asked by whisp3r3r 6 years ago  |  last reply 6 years ago


About PopSci...

I have picked up a copy of PopSci before, but at an age when I wouldn't be able to understand anything in it. So I don't remember much. After entering the contest, I did some research about PopSci. It looks cool, and if i don't have a winning project, I will likely pick up an issue next grocery trip. I was just wondering, what can I expect in an issue of PopSci and what (if you subscribe) are your favourite articles? -Evan

Posted by evy-wevy 11 years ago  |  last reply 11 years ago


about crossover?

I decided to start my own project  ---"a portable 2 way speaker with Bluetooth"--- but i have some doubts, if my woofer hit from 60hz to 10 kHz and my tweeter hit from 3.5 kHz to 20 kHz, what do you guys think my crossover should do its magic ? at 3.5 kHz or at 10 kHz ?? Or maybe any point from 3.5 kHz and 10 kHz is ok?   or im wasting the woofer capabilities if i cut around 3.5khz when it can reach 10khz thanks beforehand

Asked by javierj9 3 years ago  |  last reply 3 years ago


about button....

I have code on vb.net that will turn on led on my arduino but how can i turn it if i want to add button? how can i add button here in my code? #include int ledPin = 13; int buttonPin = 2;  // the number of the pushbutton pin      // the number of the LED pin int buttonState = 0;  // variables will change: LiquidCrystal lcd(12, 11, 5, 4, 3, 2); void setup() {   Serial.begin(9600); // set serial speed   pinMode(ledPin, OUTPUT); // set LED as output   digitalWrite(ledPin, LOW); //turn off LED      //   //         lcd.begin(16, 2);           lcd.setCursor(0,0);         lcd.print("     DaNeiL");          lcd.setCursor(0,1);         lcd.print("GASOLINE-STATION"); } void loop(){   while (Serial.available() == 0); // do nothing if nothing sent   int val = Serial.read() - '0'; // deduct ascii value of '0' to find numeric value of sent number     int buttonstate = Serial.read();       buttonState = digitalRead(buttonPin);   if (buttonState == HIGH) {         digitalWrite(ledPin, HIGH);     Serial.println("PLEASE WAIT WHILE REFUELING"); Serial.print('\n');     delay(9000); digitalWrite(ledPin, LOW);    // turn the LED off by making the voltage LOW     Serial.println("price 40");     Serial.print('\n');     Serial.print('\n');     Serial.println("liters 1");     }   else     // turn LED off:   if (val == 1) { // test for command 1 then turn on LED     Serial.println("P20.00                    1/2");     delay(10);     digitalWrite(ledPin, HIGH);// turn on LED      lcd.clear();      lcd.setCursor(0,0);      lcd.print("PRICE=  P20.00");      lcd.setCursor(0,1);      lcd.print("MILLILITERS=500");         }         {     Serial.println("P40.00                      1");     delay(10);     digitalWrite(ledPin, HIGH); // turn off LED      lcd.clear();      lcd.setCursor(0,0);      lcd.print("PRICE=  P40.00");      lcd.setCursor(0,1);      lcd.print("MILLILITERS=1000");       }   if (val == 3) { // test for command 1 then turn on LED     Serial.println("P80.00                      2");     delay(1000);     digitalWrite(ledPin, HIGH);// turn on LED      lcd.clear();      lcd.setCursor(0,0);      lcd.print("PRICE=  P80.00");      lcd.setCursor(0,1);      lcd.print("MILLILITERS=2000");       }   else if (val == 4) // test for command 0 then turn off LED   {     Serial.println("P120.00                      3");     delay(1000);     digitalWrite(ledPin, HIGH); // turn off LED      lcd.clear();      lcd.setCursor(0,0);      lcd.print("PRICE=  P120.00");      lcd.setCursor(0,1);      lcd.print("MILLILITERS=3000");       }       if (val == 5) { // test for command 1 then turn on LED       Serial.println("P160.00                      4 ");       delay(10);       digitalWrite(ledPin, HIGH);// turn on LED        lcd.clear();      lcd.setCursor(0,0);      lcd.print("PRICE=  P160.00");      lcd.setCursor(0,1);      lcd.print("MILLILITERS=4000");         }     else if (val == 6) // test for command 0 then turn off LED     {       Serial.println("P200.00                      5");       delay(10);       digitalWrite(ledPin, HIGH); // turn off LED        lcd.clear();      lcd.setCursor(0,0);      lcd.print("PRICE=  P200.00");      lcd.setCursor(0,1);      lcd.print("MILLILITERS=5000");         }       if (val == 8) { // test for command 1 then turn on LED     delay(10);     digitalWrite(ledPin, LOW);// turn on LED     lcd.clear();      lcd.print("     DaNeiL");          lcd.setCursor(0,1);         lcd.print("GASOLINE-STATION");       }           if (val == 9) { // test for command 1 then turn on LED     delay(10);     digitalWrite(ledPin, HIGH);// turn on LED     lcd.clear();      lcd.print("    FULL TANK");      lcd.setCursor(0,1);      lcd.print("PLEASE WAIT....");       }            if (val == 0) { // test for command 1 then turn on LED     delay(10);     digitalWrite(ledPin, LOW);// turn on LED                }   else if (val == 12) // test for command 0 then turn off LED   {     delay(10);     digitalWrite(ledPin, HIGH); // turn off LED           }   else {     }     }

Posted by NeilV2 3 years ago  |  last reply 3 years ago


who invented a microscope ?

About microscope

Asked by elenwaren 6 years ago  |  last reply 6 years ago



Diode current ratings Answered

How can I determine the current rating of a diode  A forward current of 2 amps is needed and the reverse voltage is 12v                                                                hopefully   Gordon                                                                                                   Thank you

Asked by GordonT3 3 years ago  |  last reply 3 years ago


New About Me (Please Read)

I am your about-average human being who occasionally stays on the computor too long. Some things that make me normal are: I hate school, I hate homework, I love music, I like football. Some things that make me different: I hate corn, I am a multi-talented musician, I like origami, I like death metal, I enjoy looking at arts, and I can burp on obey. Warnings: Do not post spam, rickrolls, or screamers. They tick me off and I get VERY spazzish. AND I HATE RAP. Tell/show me anything that has to do with rap, I will eat you alive down to your bone marrow. When you say something nice to me, I get a little hyper/excited. I am hyper most of the time I visit the chat room. When Someone bees negative, I get mad and you prob won't see me again for the rest of the day. Anyway, I am just your average person. SO DON'T RUIN IT.

Posted by Flumpkins 10 years ago  |  last reply 10 years ago


on August 16 the featured item was a tetrahedron interlocking sculpture of paper. Where can I find the steps for this?

The maker of the video spoke with an accent, possible Swedish. It was made of half squares of colored paper, each folded and made into an edge of a tetrahedron.

Asked by reby 9 years ago  |  last reply 9 years ago


Bug: Profil "about" part

I have recently updated my Profile but the “about” part is not displayed correctly. There are some &´s and semicolons that shouldn´t be there. That happens every time I have used an apostrophe in my text (That what an apostrophe looks like know: Hey I´m). What can I do to change that? Does anyone else has the same problem? Thank you very much for your help!

Posted by He Se 1 year ago  |  last reply 1 year ago


About Page Updated

The about page has been updated.  Check it out :) https://www.instructables.com/about/

Posted by Penolopy Bulnick 4 years ago  |  last reply 4 years ago


ABOUT ARM PROCESSOR?

Detailed explanation about ARM processor?

Asked by srinu.rao464 7 years ago  |  last reply 7 years ago


questions about contests

Hello i have few questions about contests: Iam in middle east, could i participate in the contest how to get the prizes  and I live in Lebanon?

Posted by buraqo 4 years ago  |  last reply 4 years ago


about robo fight?

Tell me how to use aurdino in robo fight

Asked by viralsharma 2 years ago  |  last reply 2 years ago


about mini project

am doing one mini project about light following robot....iam in need  of source coding for that.could u lend me that me for .....awaiting for ur rply..........

Asked by srinandhana 8 years ago  |  last reply 8 years ago


About image size

What are the maximum size and resolution for images ?Are images automatically resized on upload ?Thanks!

Asked by comprarmovil 1 year ago  |  last reply 1 year ago


query about soundproofing

Hey, What would be the best commonly available material to soundproof a small device? Sam

Posted by sam noyoun 11 years ago  |  last reply 10 years ago


How about...(KNex)

How about someone finding a way to make K'Nex Full Metal Jacket rounds, not expanding but fragmenting rounds? 

Posted by DrWeird117 9 years ago  |  last reply 9 years ago


Question about the contest

I justmade something realy cool! but already have an entry in the contest?Am i allowed 2 entries?

Posted by evy-wevy 12 years ago  |  last reply 12 years ago


Question about switches...

I am very new to electrical projects. Please be nice. Does it matter which side is positive or negative on a switch?

Posted by Soileau 11 years ago  |  last reply 8 years ago


Instructable about "netiquette"?

I have a question. I have an idea for an Instructable about "netiquette" (ie: etiquette on the net) Would anyone here actually think it would be useful, or would the people who need it not feel like they need it? I personally think that it may help people who need it. Any tips, suggestions, ideas, etc?

Posted by ProfessorZ42 11 years ago  |  last reply 11 years ago


Question about a instructable

 I am working a project   and i was wondering  if i should  publish it as a Instructable or as a guide ?  The title is   How to build a modern  12 x 36  Cabin on a budget....

Posted by coolbeansbaby68 6 years ago  |  last reply 6 years ago


About air compressor?

I need good explanation on how air compressor works, parts of a compressor, how to calculate pressure of air required to lift loads . please help.

Asked by mano.lingam.3 4 years ago  |  last reply 4 years ago


curious about Capacitors ! Answered

M just curious about capacitors that the voltage they store when they get charged i have two capacitors laying around for test  on one is written 400v 22uf other is 420v 100uf so how much voltage can they hold when they get charged fully ??? and any simple way to charge them ??? i want make something for shocking pranks.... :D

Asked by D3zire 4 years ago  |  last reply 4 years ago


Question about airbrush

I have an airbrush, which works very well. I was wondering if I put some very fine sand in the pot, would this work as a sandblaster, for etching designs into glass? Thanks, Tom

Posted by tomc3uk 12 years ago  |  last reply 12 years ago


Questions about a soundboard. Answered

Hello! I was recently thinkng about soundboard that would plug into minijack socket. After little research I dedcided to go with Arduino nano and DAC converter to get analog signal to jack. The sound files will be saved on the SD card and as you can see there are 8 buttons. I made the project in EasyEDA but I am not sure is it going to work. So I ask you. Thanks.

Asked by ZawszeN 1 year ago  |  last reply 1 year ago


About metal hydride?

When I fill metal hydride in tank or cylinder to storage Hydrogen gas Do I must refilling agin metal hydride to the tank or cylinder to storage Hydrogen?

Asked by Hamzaaite 1 year ago  |  last reply 1 year ago


Questions about Capacitors Answered

Does the capacitance stack in a bank? Does the maximum allowed voltage? How do you wire an SCR? How do I determine what the total output voltage/amps will be?

Asked by DELETED_Fuogger 7 years ago  |  last reply 7 years ago


about superheating and supercooling.... Answered

If superheated/cooled water is exposed to exaggerated temperatures, like 1 million° celcius or to the very depths of coldness, does it still stays in liquid form? in other words, is there a limit to superheating/cooling?

Asked by necropolian 9 years ago  |  last reply 9 years ago


Question about URLs Answered

How come some instructables are "www.instructables.com/id/CDSKBCBDSHCJ" and some are "www.instructables.com/id/title-of-instructable-here" P.S. neither of those are actually links. I know how many of you clicked on them.

Asked by kcls 8 years ago  |  last reply 8 years ago


A question for/about Vegans...

In Belsey's fabulous ible Vegan Egg, it's states that "Vegans won't eat or use animal products..." Which begs the question:  Is it unethical, or unprincipled for a Vegan to drive (or ride in) any vehicle that consumes gasoline or deisel?  Afterall, fuel is an animal by-product.

Posted by bajablue 6 years ago  |  last reply 2 years ago


Question about voltage

I am brand new here and have a question about voltage. I was reading the Instructable about how to run battery operated devices with ac power. https://www.instructables.com/id/Run-any-battery-powered-item-through-AC-power./ If I have a device that uses, for example three 1.5v batteries ill need to find an adapter that will push 4.5v. Is that correct? If that is correct, what would I do in this case? I have 20 of the same device, each of the devices take three 1.5v batteries. I want all 20 of these devices to be run on one wall plug(if possible). Does this mean that I need to get a wall plug that will push 90v? If thats the case, is that even possible? Thanks in advance

Posted by cjr187 7 years ago  |  last reply 7 years ago


Questions about Magnets

Can an electro magnet have more gauss than a neodymium of the same size?  I was just thinking about robots and advanced prosthetics. One issue with them is they require rather bulky motors to get the lifting and holding capacity we often require. So if power wasn't an issue and you could make a small elecro magnet that has more gauss/a stronger magnetic field than a neodymium magnet. Than we could make strong and smaller motors.  Just a thought. Discuss!

Posted by mpilchfamily 4 years ago  |  last reply 4 years ago


Question about Sugru.

For anyone that has used Sugru in the past, how much grip does it have once completely cured and dry? I was wondering if I could use it on the outside of a 3D printed wheel to get good grip like a rubber tire. If not any suggestions for other materials I could use? Thanks!

Posted by Patrick S 5 years ago  |  last reply 5 years ago


A Question about transformer? Answered

In transformer formula , the primary turns and secondary turns affect the voltage and current directly. Why some transformer output voltage is affect by frequency and core type , just like Flyback Transformer(LOPT) and Tesla Coil specifically is Solid State Tesla Coil?

Asked by james34602 6 years ago  |  last reply 6 years ago


Help about PCB? Answered

Hi Guys, I happen to be stuck in a situation in which i need a pcb but only have a schematic and do not know how to make a pcb. So I was wondering if anyone ov er here could design me a pcb from a schematic (provided below). Help will be greatly appreciated. Thanks.

Asked by SA-DIY 2 years ago  |  last reply 2 years ago


About the drone contest:

I read in the desciption for this contest: Individuals and small groups (from universities and hackerspaces) will be creating projects around airborne autonomous and radio controlled vehicles. So does it only count if you enter with an instructable for a flying autonomous vehicle or does any kind of radio controlled project count (like a car or a boat)?

Asked by Bauwser 5 years ago  |  last reply 5 years ago


Question about thermodynamics??? Answered

The zeroth law states that any 2 or more objects that come in contact must exchange energy to create a thermo equilibrium.  Would 2 magnets of the same polarity in a vacuum still abide by this law?  Can someone give me a formula to explain it?  Can magnetic fields even make heat by themselves or rather is there any friction between the two??  Thanks much!

Asked by shawneegeek 8 years ago  |  last reply 8 years ago


About adding Shortcuts

I am new to Instructables. I wanted to add shortcuts and I want to make the Instructables to be displayed in one single page(by selecting the tick mart). I added all the shortcuts and I selected the tick mart and pressed on the save option. But the save option is not working. I tried almost 5 times but of no use. Can anyone Please help me to overcome my problem? Thank You

Posted by kiran1933 9 years ago


Questions about led

Hi! 1 :trying to find out if there are any  problem (caused by the red leds lower forward voltage) or not to drive blue and red leds with the same driver when connected in series.  2: if you drive  blue or  red led with lower capacity than rated (ex 2w instead of 3w) could that affect the wavelength for resp color could a red 660nm become a 630nm? the questions concern a growth lightsource thanks  

Posted by kristerh 5 years ago  |  last reply 5 years ago


Questions about relays

I am building a robot with a specific purpose and I have hit a snag. My remote controls on the receiver end are 4.5v and the motors I want to run are 12v all of it is DC. The relays I have don't pull in a 4.5v so I need another way to doing this. I either need another way of pulling in the relays; I need relays that pull in at 4.5, or some other intelligent solution that I cannot think of. Please help!

Posted by kendallickes 10 years ago  |  last reply 10 years ago


Yeah, About The TNKIT..

My computer crashed at home, the stupid thing always fails on me at important moments. I'm writing this from my school's mediacenter, and i don't have the scores here, so i thats why i haven't made a round 4 yet. I'm terribly.. terribly sorry, but i can't do anything. Hoping the damn thing will be up and running soon, but for now, start building something to keep your skills up. Good luck in advance, Viccie.B1993

Posted by Skreetsha 9 years ago  |  last reply 9 years ago


what about minidisc?

Does anyone have any clue as to how you could take minidisc components and somehow add them to a computer? i have an old sony portable MD player that i ripped apart and was curious as to why no one has tried this? there must be a way to do it because i thought i remembered there being an old Sony VAIO that had a built in minidisc drive on the fron of it. maybe i am mistaken, i dunno, but please let me know if there is any way of doing this! thanks!!

Posted by cameraguy1976 11 years ago  |  last reply 11 years ago


about a electircity problem ?

I'm trying to help my neighours & some of my relatives to invent some solar electricity inverters for our daily uses along with OUR native  country NEPAL to solve our NATIONS requirements. SO, will anybody gives us any IDEA or SOLUTIONS for free of cost ?? So, we can boost our Nation's PROGRESS in OUR own term and Conditions ??? if so  please send me an e-mail to my account. It's suleman#e-pao.every1.net

Asked by imgood 9 years ago  |  last reply 9 years ago


advice about timer?

I need cheap small timer to use in my device ( voltage protector) to use in control of warranty of 3 months, this timer will connect to led and when the time is finish (3 month of real working) the led will off, this timer should calculate the time of electricity working only ( if electricity cut off the timer not calculate the time when there is no electricity)  the timer continue calculate the time of working only is case of electricity is exist. when the total time of electricity on (exist) reach 3 months the timer will cut off the power on the led so will turn off the led

Asked by rubellamarket 4 years ago  |  last reply 3 years ago


Question about Led's

Recently I took apart one of those dollar store led flashlight's. There is 5 led's in it . all the +  anode were connected to each other and all the - cathode were conected to each other and they were conected to 4 button cell batterries no resister or any thing else does that mean that each led runs on 6 volts and as long as I use a 6 volt dc battery they should work fine without a current limiting resistor and if I run them in series I could use 12 volt battery. the led's look white but they give off a blue light?

Asked by sml156 9 years ago  |  last reply 9 years ago


Question about Grammar

I've noticed a lot lately, people using their internet grammar (not just here), and then defending it when they get criticized for it by saying something along the lines of, "wat r u a teacher?" or, "idc im not n scool rite now." So I have two questions about it, one for our adult members who grew up before the internet, and one for our current youth members.For the adults:Did kids tend to use proper grammar outside of school as you were growing up, or did they use the same sort of excuses for poor spelling and grammar? I guess this applies mostly to letters and notes to each other.For the youth:Do your peers use the same abbreviations in written communication outside of school as they do online or in text messages? Also, how predominately to you see internet speak used around you, compared to those who use proper grammar and spelling?Thanks! I look forward to any input you have on the topic.

Posted by Weissensteinburg 9 years ago  |  last reply 9 years ago


Question about Resistors Answered

I have am writing an arduino sketch for a mini traffic light projects that will require both 220Ω & 330Ω resistors, I ordered them, the problem is that the resistors I received don't add up when looking at the bands. this is the color band  ORANGE+ORANGE+BLACK+ORANGE+BROWN 3 -------------3------------0----------x3------------1%-------- does not this mean 330 x 3 @ 1% so the 330 is actually 3,300 or would it be 330kΩ It's been years since I've looked up color bands , can I even use these ones for simple 5v led projects or should I just re-order the 330Ω resistors now? thanks in advance robert  

Asked by rdlockrey 2 years ago  |  last reply 2 years ago