Anode and cathode metals? (For electrolysis)

I want to seperate some water to get Hydrogen to play with, so I made a little electrolysis device with a 12v power supply. The only problem is that I have no idea what to use as the anode and cathode! Could I just use screws? Or pennies or something?

Topic by Login258   |  last reply


Re-anodizing a macbook pro? Answered

I am getting an old macbook pro in the mail soon and am going to have to pretty much tear it down completely to repair it. I have seen a few guides on anodizing aluminum, and was wondering if maybe, possibly I would be able to anodize my macbook to a different color! Would this require de-anodizing the aluminum? (the model is a late 08 macbook, so I dont know if that is a powder coated one).  It would be awesome If I could color it a nice matte black (my preferred color) Has anyone attempted doing something like this before? I have some scrap brushed aluminum to practice on.. would that work? I know this could be easily accomplished with a black case... but I kind of want to go a bit further than that... 

Question by astroboy907   |  last reply


Anodizing cooper tubing, can it be done?

Is it possible to to color pain houper tube by anodizing?

Question by vallka   |  last reply


Can I fit a 10W heatsink in a zippo? Answered

I want to put a cree XM-L LED in an old zippo, and I want to know if anyone knows how to fit a big heatsink in the top part of a zippo lighter, not in the base, and preferably able to buy everything from a hardware store, not ordered online.  Also, does anyone know how to anodize aluminum for added heat dissipation?

Question by jduffy54   |  last reply


Arduino Current Sourcing for Common Anode RGB

Question: Is it safe for the arduino to sink more current then the arduino is sourcing? (see diagram below) My project requires 12 of large 10mm RGB leds,  broken down this is 36 leds in total, which exceeds maximum draw,  the design calls for the LED's to share a 5v+ from a seperate 5v regulator, then sink each pin to low to turn them on is this correct?

Question by rdlockrey   |  last reply


3w common anode RGB LED circuit?

Hi all,Does anyone have a link to a circuit diagram for a common anode led? Here are the specs:Red: 2.5V ~ 3.0V, 350mAGreen: 3.2V ~ 3.8V, 350mABlue: 3.2V ~ 3.8V, 350mAI picked one up and didn't realize the effects of common anode v. common cathode :/ I can run it with drivers from one of the instructables floating around, but I have to use totally isolated power supplies (i.e. one separate battery for each color). I realize that I could use PWM for them, but I don't have the tools to program and burn a chip right now.Soooo, either a circuit that can sink current (I believe that is the correct terminology) or some way to isolate power between the 3 colors would be much appreciated.Here is a link to the led I have: http://www.dealextreme.com/details.dx/sku.4530

Topic by homba   |  last reply


Resistor values for common anode RGB LED? Answered

Hi,  I have 10w RGB common anode LEDs. Forward Voltage is R:6-8v, G:9-12v, B:9-11v. Forward current is 300ma.  I calculate resistor values as R:15ohms, G:1Ohm, B:3.9Ohms.  This is based on max Forward Voltage.  I was told I wouldn't need resistors but clearly that is not the case as in one of the LEDs the red has failed.  Is it as simple as putting the correct value resitor between each cathode and supply?  Also, if I were to increase the resisors to lower the voltage a little (i.e. R:7v=18Ohm,  G:11v=3.9Ohm B:10v=6.8Ohm) would that help keep the heat down? Many thanks,

Question by Summerly   |  last reply


How can I color aluminum wire without annodizing?

I bought a spool of 14 gauge aluminum wire for chain maille. My goal is to have alternating black and natural colored rings used for the maille. In a household metal working book I found from the 80's, they said to,"Mix 2 tablespoons lye into 1 quart cold water. Add aluminum part for 1-2 minutes. Submerse part into household dye mixed according to manufacturers directions until desired depth of color is achieved. Rinse in cold water".I tried this method using RIT black household dye; however, it was not successful. I am trying to dye the wire both RED and BLACK. If no method for the red is found, I can purchase a short length of anodized red wire; however, If there are any chemical reactions for turning the wire black, that would be great. Thanks!!

Question by kreationism   |  last reply


i need help connecting led cube anodes to pic16f690?

What led base anodes do you con nect to the pic and which pins

Question by zane20062 


common anode and common cathode differences in 7segment display

What are the changes need to do when using common anode seven segment display instead of common cathode seven segment display. hint:use transistors?

Question by nethmi.amanda.3344   |  last reply


How do I use a Common Anode 7-Segment LED? Answered

I have a SA23-12EWA Common Anode 7-Segment LED and I can only get the decimal point to light up. How do I connect it so that the other segments light up?

Question by powerman666   |  last reply


In a vacuum tube, are the anode and the cathode connected in any way? Answered

In the wikipedia article, they refer to the cathode as a filament, which I thought was a bit odd. The only other filament I'm familiar with is in a light bulb. I was reading a book about vacuum tubes earlier, when I looked them up in wikipedia searching for a diagram: vacuum tube. Basically, a vacuum tube is a capacitor with a vacuum as the dielectric? Does a vacuum tube retain a charge? They seem to have the same principle: anode, cathode, dielectric. In a way, a battery seems to also be similar; the difference being the galvanic process involved. I attached a picture of a Daniel's cell from back in the day.

Question by Vorenus   |  last reply


Would this battery work?

I want to make a compact battery, I need it to generate as many volts possible. The battery materials are the following: Anode: Zinc Cathode: Steel Electrolyte: Sulfuric Acid Is that the optimal anode and cathode I can use to get most volts out of it?

Question by Nitr0   |  last reply


Sanding Laser Etchings and Saltwater Etching Through Anodization ?s

I own an iPod Shuffle, 2nd generation, silver. It is very plain, and I've recently been reading up on saltwater etching. I want to remove the standard Apple logo from the back and etch my own text (it will either be "iMake" or "iBles", I can't decide). I've come upon two roadblocks, so far, those being: can I sand laser etchings (the Apple Logo) off, and can I etch through the player's anodization, or would I need to sand that off? I don't really care if it doesn't turn out perfect, or looks like a total mess. It's not like I paid for the thing. Thanks for any help!

Topic by Bran   |  last reply


How can you tell what is the anode and cathode on a tri-color LED--it has 4 leads? Answered

Its this LED here also what is the best way to hook it up www.radioshack.com/product/index.jsp

Question by Fresnel110   |  last reply


I have a question about electrolysis...

Why doesn't it work when I put the anode and the cathode in two different container when I am separating hydrogen and oxygen from water in electrolysis...?!

Question by nicki0850   |  last reply


i want to control 5 common anode RGB led's with my arduino, i want them to fade throgh the color spectrum amy thoughts?

I have 5 common anode RGB led's, which i am building into a lamp setup for a present. as well as controlling them with my arduino, I would like the ability to manually adjust the color, my budget is 50 dollars, and i have 2 weeks to complete this project. i would really appreciate the help.

Question by jamesr370   |  last reply


Using Common Cathode Instead of Common Anode rgb led with IC?

So I'm trying to do this: https://www.instructables.com/id/RGB-LED-Color-Sequencer-without-a-Microprocessor/ and I realized that I have the wrong kind of led..the author says you have to "adjust the connections" but I don't really know how. Right now my led will glow but not change colors. Does anyone have experience with this?

Question by njaber   |  last reply


9 pin, 1/4" input/output. Which pins are the anode and cathode? [PIC]

I have an 9(?) pin 1/4 input/output. I got it off an old radio. Which of these 9 pins would be the anode and cathode? Looking at the pins, starting from the top there are 3 rows. the first row has 1 pin labeled (1). The second row, 4 pins labeled from left to right (8, 7, 4, 5), last row, 4 pins (9, 3, 2, 6) Any help would be amazing, as I am trying to ghetto rig a distortion pedal.

Question by surlistyc   |  last reply




What metal doesn't react with sodium? Answered

I am trying to make sodium. I used graphite and copper wire at the anodes and cathodes. Both of them combine with the sodium and corode. That leaves me with 0% sodium.

Question by chinarian   |  last reply


RGB Led doesn't mix colors

Hey all I am working with common anode RGB LED. I hooked each leg (red, green, blue) to pins 2-4 of my Arduino UNO. I then hooked the anode to 5v via a 22 ohm resistor. The code I wrote was very simple; turn pins 2 through 4 low, delay 500, turn pins 2-4 high. The problem I found was that instead of the color turning white it stayed red. I tried mixing red with green and red with blue, each time same thing it stayed red. Does this sound right?

Topic by Mpc1055   |  last reply


How can I create a manually controlled rgb led controller?

I have a 4 lead common cathode led.  Would it be as simple as building an led driver circuit and placing a potentiometer between supply and each anode?

Question by chandlerman   |  last reply


What practical applications do PNP and NPN transistors have? Answered

I read about NPN and PNP transistors and I was wondering what type of applications are right for each type of transistors. I understand that depending on the type of transistor the emitter should be connected to either an anode or cathode.

Question by blkhawk   |  last reply


RGB-LED with 6 legs? Answered

As far as I know, RGB-LEDs have 4 legs: 1 common cathode and 3 seperate anodes (or vice versa). Santa Claus has left me a RGB LED with 6 pins. Now I'm confused and he has left the country! Can anyone help and explain this to me?

Question by bertus52x11   |  last reply


stop 7-segment from ghosting?

I'm working on a simple arduino 7 segment driving circuit. (It also has a led bar-graph that displays binary numbers but that part is working fine.) When I get the display working I might make an instructible out of it. Here's the basic layout: -using this 8 segmet 4 digit common cathode display. -arduino controls what segments are on via 74HC164 8-bit Serial Shift Register -shift register controls an array of 8 PNP transistors with base and pull-up resistors -transistors connect to display anodes through resistor array -display cathodes (common for each digit) connected to array of 4 PNP transistors with base and pull-down resistors  -PNP transistors controlled by arduino. (I will post the schematic shortly.) In software, to display a four digit number, I shift the pattern for a given digit to the shift-register, which in turn turns on the PNPs for the corresponding segment anodes. I then turn on the NPN for that digit's cathode. I delay for a few milliseconds, then turn the NPN off, shift the next digit in, and turn the NPN for that digit on. Rinse and repeat. It works fine but the segments that should be off are at about 1/2 brightness, making all the digits look like eights. Even the DP looks like it's on and I'm not turning it on anywhere. Do I need pull-down resistors for the anodes or something? What's going on here?

Question by Vick Jr   |  last reply


How should i clean painted brushed steel?

I'm currently working on the restoring of a Philips 748 from 1979 and i want to clean its  frontal plate, which is brushed steel with what looks like electro painting. What can i use that wont ruin the paintjob?

Question by vinacarv   |  last reply


What are the specs for 'standard' 3.5mm mono pluged infrared (IR) emitters?

An example of what I'm talking about can be found on Amazon.  I am looking for which conductor is anode and which cathode as well as the forward voltage and current requirements.  My inability to see IR is really hurting my normal LED testing techniques.

Question by EmperorMing   |  last reply


Make Led cube? Answered

Hi, I want to make a 4x4x4 led cube ? Please tell me which is the best instructables to make a cube? Which cube is good common anode or cathode? I want to make the cube with a arduino uno I find  a  instructables - https://www.instructables.com/id/4x4x4-LED-Cube-Arduino-Uno/ Is it good to make and is it need any transistor?

Question by Soumojit   |  last reply


Animatied 3x3x3 LED Cube !

A guy named "portreathbeach" built this simple 3x3x3 LED matrix. It uses a PIC16F690 in a ZIF socket for the brains. Each layer has nine LEDs with the cathodes tied together. The anodes from each LED are connected to the LED below. The LEDs are multiplexed so that even though all layers appear to be on, they're being addressed individually. Video of the matrix in motion below !!

Topic by =SMART=   |  last reply


how would i wire my 5x7 led matrix to work with 74hc595 and arduino? Answered

i have a really neat 5x7 led matrix from a recycled led sign from a surplus store and the rows are anodes and the columns are cathodes. i would like to get it working so that i can display messages on it.

Question by devicemodder   |  last reply


Using a 74141/7441 or KM115

I'm having much difficulty understanding 74141/KD115 chips. Do I supply the Vcc and GND pins with the 140 volts I'm using to drive the nixies? I'm guessing that each output of the 74141 would go to each of the nixies anodes, but do not know this for sure. A quick tutorial or explanation would be much appreciated. Thanks, -B.

Topic by B_A_M   |  last reply


Rgb matrix, looking for some advice/guidance.?

Hi, its been quite some time since Ive been here. And I still have the same two projects in mind. However, the project im more focused on, is a 32x16 RGB led matrix. Made up of four sections. Im following the project by the two guys over at solderlab.se. They arent very active and speak a different language so their english explanations arent as thorough as Im looking for so I figure id ask the people here :) So, the main questions I have: 1. What kind of material can I use to put the leds on? its like they use thick cardboard or wood. they drill all four holes per led so the legs go through. I want one big board instead of two.  2. What spacing would be good to make it look uniform, yet give enough space to solder?  3. How can I make the 4 controller boards to run it? - They sell them, but they arent cheap. And they dont deliver or sell to the US. So Ill have to make them somehow. I can provide images/part list of what they used.  4. What type of solder/soldering iron would I need? Obviously various temp. But what temps would be safe?  5. What power supply can I use? Ok so, any other info: -They used common anode LED's  -They connect the boards together via ethernet cable.  -They connect the led's together in four sections of 8x16, The anode is connected on each of the 8 rows. And the anodes on all the led's are connected on the 16 rows. If that doesnt make sense, the anodes are connected vertically, and all the cathodes are connected horizontally. -They connect the 48 cathode wires to ribbon cable, that goes to the controller board, same with the anode wires.   -They connect the boards to a Usb to UART connector -Lastly, Part list of one controller board:  HEXFET IRF7314 x4 TLC5940NT x 3 28 Pin IC-Socket 300mil x 4 Resistor SMD 0,25W 1% 10K x 10 Resistor SMD 0,25W 1% 2K2 x 8 Resistor SMD 0,25W 1% 2K x 3 Resistor SMD 0,25W 1% 220R x 2 Resisitor SMD 0,25W 1% 1K x 3 AtMega 328P x 1 74HC138 SMD x 1 Ceramic Capacitor 22pF, 20% x 2 Oscillator 16,0 MHz x 1 Pinheader 2x8 Pitch 2.54mm x 4 Jumper x 3 Pinheader 1x2 Pitch 2,54mm x 7 Modular Jack x 2 Ceramic Capacitor 100N, 20% x 5 Electrolytic Capacitor 680uF x 1 LED 5mm blue x 1 LED 5mm green x 1 Screw terminal 5.08mm x 1 If theres ANY more info required please ask. It said to be as detailed as possible.

Question by 'earl   |  last reply


how to connect 5MM RGB led to connect with 12v 6A controller?

Dear all,  i am bit confused and want your expert help for following matter. 1. I have 12v 6A (2A X3 each= 6A)  RGB contoller  : as this link http://www.ebay.in/itm/24-key-IR-Infrared-Controller-remote-12V-power-Adaptor-fr-RGB-Strip-flood-Light-/161201011884?pt=LH_DefaultDomain_203&hash;=item2588543cac  2. I have 5 mm common anode led: as this link  http://www.ebay.in/itm/RGB-LED-5MM-Common-Anode-20pc-Set-/151542871353?pt=LH_DefaultDomain_203&hash;=item2348a8b539 i want to connect this 5mm common led total 6 nos with above mentioned 12v 6A RGB contoller.   how to connect it safely so that led will not burn . because red needs 2.2 v  , 20 ma , blue and green need 3.2v  , 20ma  to light up. and source is suppling 12v 2A . i think if i connect it directly . it will burn the led. 

Question by YOG PATEL8186   |  last reply


LED, bipolar diffused common-cathode ultra wha?!

I was browsing through one of my local supplier's LED catalogue..Literally overwhelmed by the types of LED out there.. Diffused, non-diffused, super flux, super bright, ultra bright, common anode, common cathode, flashing, bipolar, etc..Anyone care to enlight this electronics noob? Plus some of the LED spec says something like 630nm, 1800mcd, what do they mean? Thanks..

Topic by gyromild   |  last reply


Coding to controll a 4x4x4 led cube with arduino duemilanove... Help please?

Okay, i know how to build the cube and to multiplex it to use only 12 pins. what i am going to do is connect each anode of each level and connect each cathode of each row, and each one will go to its own transistor. so i will have a total of 8 transistors for the anodes and 8 transistors for the cathodes, which i can further multiplex into two groups of 4x2 transistors. that makes a total of 12 pins on the arduino(i hope that makes sense ill add pics of what i mean to help) but what im asking is that i need help on writing the code for this project. i have a basic idea to run loops inside of loops to make more than one led look like theyre on at the same time(i believe its called persistance of vision)  but maybe someone more experienced would be able to help me out with this. thank you to anyone helps and A Happy New Year To All Of You!!!

Question by the seaker   |  last reply


How do I get a 7-color LED to just blink continuously?

I'm working on a sculpture that involves LEDs.The basic instructions I've been using come from steps 2 and 3 from this tutorial - https://www.instructables.com/id/Beating-... I'm attaching the leads of the LEDs directly to 3 volt lithium watch batteries. However, I decided to try to use a 7-color blinking LED, and I'm having troubles.The LED packaging says it has "single-color, color-changing or flashing modes." The LED has one anode and two cathodes. When I attach the anode and one of the cathodes, nothing happens, and when I use the other cathode, it cycles through all of the modes in about 30 seconds, and then turns off. The only way I can get it to start again is to take the leads off and start again, but this isn't an option for my project, being as the entire circuit has to be covered in glue to waterproof it.How do I get the LED to just blink continuously? Any help is greatly appreciated.

Question by hezzer   |  last reply


Can Someone help me to program an arduino uno?

I have an arduino uno and i wired a 3x3 led matrix to it. I really have no idea how to make any code for it to light up in any pattern or anything. I have the cathodes connected to pins 3,5,6. and the anodes connected to pins 9,10,11. Can anyone help show me a link or something that explains how to program it, or give me a sample code to use? thanks

Question by texpert   |  last reply


rgb with out a microcontroller (beam-ish?)

I have been trying to contemplate how to make a rgb random oscillation, with the option of pressing button 1 for red button 2 for blue button 3 green. with no micro controllers, unfortunately I cant seem to do it most of my concepts run in to problems. any advice would be appreciated. preferably in the more helpful verity. bare bolts and brass tax is the point of this, i will be making a instructable for it if i can figure it out. the led's are common anode.

Topic by CD_tatro 


Phototransistors interfacing with a serial port

So I really don't have too much experience with interfacing stuff and PCs (read: none) and I have a question. If I was to wire up about 5 phototransistors in series, all with a laser aimed at all of them, with the anode hooked up to TxD, and the cathode hooked up to RxD, and I had a program sending 500 bits to it per second, and checking for response.. will it basically be able to detect if one of the lasers are broken? Thanks!

Topic by cvxdes 


LED cube project

Hey guys ,so was in progress of making the https://www.instructables.com/id/LED-Cube-4x4x4/step7/The-controller/ and i'm stuck on the controller step, a lot of people ware stuck on this as I see from the comments, and I can't find any help, would someone mind helping me? I have several questions, if you have time, I'd appreciate it if you answered them!  after zooming into the drawing, few questions remain: - resistors for the cathode and anodes, what resistance should they be? I'm powering this cube with 5.7v 1800ma nokia charger, current LEDs of mine run with a 120k ohm resistors, would these do fine?(connecting to the chip)  - On the left hand side, what are the 5V + > , GND connection mean to do? do they connect to the cube? or?  - also the connection 18-21 that have resistors and then are linking up to... cant read the writing, im guessing it should be the anodes as thats the forward current?  Hope someone could answer these for me? THANK YOU so much!  After i'm done making this project I will hopefully be able to make an easy to understand diagram for newbies like myself so they can work out this circuit themselves and wouldn't give up 

Topic by saulyx   |  last reply


Can anyone help me program this 8x1 LCD with Arduino?

I'm having trouble programming this 8x1 character LCD. It's not compatible with the Arduino's LiquidCrystal library. The manufacturer failed to give a detailed datasheet. This is the supplier of the product: click Here's the Pin Map (according to supplier) : 1.) Gnd 2.) VDD (3.3v) 3.) CS Input 4.) SCL - clock signal input 5.) SI - data input 6.) /RES - reset signal 7.) Backlight Anode (3.3v) 8.) Backlight Cathode (Gnd)

Question by ASCAS   |  last reply


RE: Colloidal silver generator upgrade. How can I ? keep my electrodes clean

I made a colloidal silver generator that operates on 31.8 volts at .30 ma . It works good but I hate cleaning the electrodes every hour. How can I add a automatic switching device to swap power to my anode & cathode reversing power every so often to help keep my electrodes clean. any advise would be helpful. Thanks

Question by jamesskytown   |  last reply


why are the resistors heating up?

So i have 48 UV LEDS and each has a 470 ohm resistor on the anode so in a sense all leds are connected in parallel but it has a resistor on it. when i connect my 12 volt battery with 6500 MA the resistors begin to heat up. is there anyway to prevent them from heating up? or what is it that im doing wrong. ill provide a picture on the way the leds and resistors are connected if you want me to but hopefully what i said gives you an idea on how they are connected.

Question by diabloboy   |  last reply


Silver recovery from photographic fixer solution at home level.

I wa trying to recover silver from photographic fixer solution using home made electrolysis unit having 12v and 3 ampere DC source, small graphite, and stainless steel dinning plate, plastic container of 25 L size.  But, after 6 hours, i was unable to get  the expected more than 60gm silver. in fact i get nothing at all. Why it went wrong? what is wrong with the anode, cathode, power voltage and amperage, volume of fixer used, NaOH added---? With regards!!!

Question by dese 


How do I recover the silver from unexposed B/W photo paper?

I have several hundred unexposed sheets of B/W RC photo paper. I know I need to use a fixer and a cathode/anode set-up. What is a simple, easy-to-obtain or make fixer, and what voltage/amperage combination do I need? As I remove the silver from the fixer, can I reuse the fixer pretty much indefinitely? What do I use as electrodes? All help is appreciated.

Question by jaxboy   |  last reply


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?

Question by sml156   |  last reply


Building a 3 x 3 x3 LED Cube controlled by an Arduino?

I built a 3x3x3 LED cube and tested it. Since I'm new to electronics and micro programmable processors I'm having a difficult time connecting the cube to the Arduino and haven't had much luck getting information fundamental enough for me to grasp. I've tried a few ways and as you would expect, trashed a few LEDs to say the least. Since the digital pins output 5 volts I can't figure out how to connect the  9 anodes and the common cathode per level.  Can anyone help? Thanks, 

Question by happywatt   |  last reply


Wiring stripboard tracks to common ground

I'm planning a stripboard POV kit to solder with learners over about 3 hours or so, and I have a problem designing the wiring for the LEDs. It's straightforward to use the required series resistors to wire the output pins of an ATMEGA like http://www.arduino.cc/en/Hacking/PinMapping to the anodes of 8 5mmx2mm rectangular leds like http://www.rapidonline.com/Electronic-Components/Kingbright-L-383IDT-5x2-5mm-H-i-Red-LED-Rectangular-56-0398 packed side by side onto 0.1 inch stripboard. However, I'm facing a puzzle when trying to wire the LEDs' cathodes together to ground. It's fairly easy for me myself to do this, just by free-soldering a couple of spare legs directly over the cathode tracks, or chaining loads of wires. However, I can't see myself guiding 45 people through this in a workshop without hassle and errors. Does anyone have a simple way to wire 8 'odd' stripboard tracks together to a ground track (the 'even' tracks have the anodes in them). To give a flavour of the solutions I'm considering, I'm looking into 0Ohm bussed resistor networks like http://www.interfacebus.com/resistor-network-schematic-bused-resistors-sip.html to wire theparallel tracks into a single ground track using a standard through-hole component with legs clipped off. However I'm having trouble sourcing anything like this, and I'm sure others have better ideas.

Topic by cefn