# COMMUNITY

### Scientific Theory

I am working on a scientific theory and I need a little help. I have 2 car batteries in series to create 24v need to power an electric motor. The motor is 14.5 amps and I need a way to control the amperage from the car batteries to the motor. Any help would be greatly appreciated.

Posted by Ice Dragon 5 years ago

### Really basic Resistance / Amperage question:

Before I begin: yes, I should know this already, but I'm really sleep deprived right now, and therefore slightly muzzy on my electronics knowledge... My circuit has two loops running in parallel off one, limited, 18v power supply: [*] Loop 1 requires the majority of the supply's power to run [*] Loop 2 is simply a 7805 voltage regulator supplying 5v to an analog input on an Arduino, so needs almost no current running through it. [*] when Loop 1 and Loop 2 are both active, Loop 1 does not get enough power. if I place a resistor in Loop 2, in series with the 7805, will it increase the amperage to Loop 1? I think the answer is yes, but, once again, I'm MASSIVELY sleep deprived. any help is appreciated.

Posted by gschoppe 9 years ago

### Higher Amperage

Hello guys, i need help with one of my projects.I have make an DIY Keyboard with neopixel at any button,it works perfect but i have problem with power. i have 2 usb from keyboard one for arduino and one for keyboard.if i load #define BRIGHTNESS         20  all is good but if i load #define BRIGHTNESS         80 the usb connection is lost and arduino start to lag.this is amperage problem and the question is if any1 know how i can take that usb output from pc and make it with circuit to higher amperage.

Posted by NetariaT 7 months ago

### Some sort of microcontroller to regulate accessory power usage in a car?

So as most of you know, I'm working on making a hydroxy booster for my car. That's not too hard. I'd like to build some sort of microcontroller-device-thingy that would regulate how much amperage the generator draws, based on the load required by the car, so as not to draw too much. Is this something for adruino or..? I'm kind of clueless on this one so.... PLZ HELP!! I'm fairly unaccomplished in programing, but I could learn something if it's simple enough.

Posted by KentsOkay 8 years ago

### Minimum voltage/amperage required for peltier cooler?

I want to connect a couple of computer fans and a peltier cooler to some solar cells, but I want to keep the amount of electronics to a minimum (for the sake of KISS). Assuming the fans and peltier are rated to run at 12V, and I connect the solar cells to provide 12V at peak, will I be able to leave it connected all the time, i.e. when it's night time there is no electricity being provided, maybe in the late morning there is half the electricity, and in the afternoon sun full power? I guess a simpler way to phrase my question is: Can these devices be run with much lower voltage or amperage than they are rated for?

Posted by littleb28 6 years ago

### LED burnout

I've been having trouble with LEDs. I'm running 18 blue ultrabright in parallel. The specs for volts and amperage are as follows: 3.6v typ 4.5v max 20ma typ 30ma max Each LED has a 220 ohm resistor which was calculated for a 9v source with each LED at 4v, 25ma. This seems well within their range. But, in about a year and a half's time, I've had about 25% burnout. Most of the others are showing signs of intensity and spectrum degradation. Any thoughts as to the cause of this?

Posted by hexedene 10 years ago

### PCB Trace Width Questions

Hello instructioners, So i am working on a PCB to use my XBOX 360 power supply as a standard 12volt 16 amp without hacking it apart. I've taken the female plug from a dead Xbox and I've recreated the layout in ExpressPCB. my only issue is being that its 16 amps @ 12volts is the trace widths to hold that much power are ridiculously wide we are talking 7mm or there abouts. I used several different online calculators to determine trace width.  My question is..  how small can i get away with for traces and still get 16amps.. is there a way of bridging the front and back side of a 2side PCB to allow for more amperage on smaller traces? i am really at a loss here. since my PCB is set at 38mm by 38mm and the connector size is 27mm long by 23mm wide. with 7mm wide traces i can't connect all the power pins together and all the ground pins together and route them out. Now i realize the 16amps is max draw but i'd like to plan for a max draw situation that way i feel confident enough to not have to check it all the time to make sure its not melting. Below is an image of the current board in Express PCB the labeled Thru-hole are connections i will need to make for this all to work. the other remaining holes are for mounting the female jack securely. The three yellow boxed connections are 12v+ The three greyed boxed connections are gnd ENG is bridged to +5 to make the XBOX PSU provide 12v

Posted by jgosselin 6 years ago

### LEDs - Under-volt, over-amped?

My issue: Have multiple LED drivers, (high power LED instructable) and connected the wrong one. The LEDs are not dead. My LEDs are rated at 9-12v, 950mA and I have sets of 4 in series hooked up to a 36v power supply. The driver I used has a .3ohm resistor on it. so it's putting out ~1.3A The LEDs should have burned up. Since the driver eats up a little of the voltage, each LED is getting ~8.75v. Is this why they haven't burned up? Thanks!!

Posted by thestip 1 year ago

### Component Amperage Rating

Hi! I was browsing through an electronics retailer website looking for components to buy (particularly a LED) and i was wondering what the amperage rating of each component meant Does it mean: 1. the current flow across this component shouldn't be more than the amperage rating as it will cause damage? 2. or the current flow across this component should be equal to this amperage rating? please help me I'm really confused :(

Posted by La Tour Rouge 9 years ago

### Discharging high amounts of amperage in a very short time.

Previously I asked this question, except I wanted to build an electromagnetic dent puller. But no one gave me specific ideas or instruction of how it could be done, instead everyone told me different ways to pull the dent out, or how the metal looks.. Anyway. I have a lot of copper wire. And I have a bunch of magnets and ferrous cores, iron rods.. etc. I am wondering if I can create a very powerful burst of magnetic energy with a few winding's of copper around a ferrous core. I'm talking enough to push two very heavy objects apart, such as a television or couch... 1) Copper will be wound around about 40-60 times 2) High amperage discharge from capacitor bank 3) Possible explosion or melting wire? Thank you... again

Posted by Justdoofus 5 years ago

### Low Voltage Higher Current?

Posted by edy 6 years ago

### How do Transistors handle Amperage?

Hey, I'm working on a wireless power transfer system and I'm planning on running it on 12vdc with a 2n3904 transistor, but my power supply supplies 2 amps. Now the question is, will the transistor draw only the current that my transmitter coils draw, or will it simply draw it all for supplying the coils. I have not yet determined how many turns or what resistance they have yet, I'm still in early stages. I just don't want to ruin one of my few transistors. I know the absolute maximum current this specific transistor can handle is 200ma.

Posted by DecemberRain01 2 years ago

### Voltage Stabilizer Efficiency Loss (Extra power consumption)

Hello All, I am using an 1KVA Voltage stabilizer for my Fridge. The power quality is really poor here in India, and these things are mandatory. I learnt the lesson hard way :-(.... Well that aside, i would like to know what would be the power loss or Extra consumption these devices use when regulating power. Actually,i could use a general lecture on how Stabilizers work!

Posted by bhvm 5 years ago

### ATX PSU to Work Bench PS - Adjustable Voltage and Current question

I am working on converting an old 600W ATX PSU to a bench power supply for me to use for some lab work.  Not everything that I will be plugging into it will have built in current limiting capabilities.  The guide/setup i found on here that I will most likely be following are:  https://www.instructables.com/id/DIY-PSU-into-Bench-Power-supply/  &  http://www.wikihow.com/Convert-a-Computer-ATX-Power-Supply-to-a-Lab-Power-Supply The first link is how I would like mine to end up looking. My PSU is rated as: +3.3V @ 32A +5v @ 50A +12v @ 24A -12v @ 1A -5v @ .5A My end goal is to be able to control the voltage and current output from each binding post.  I will be hooking up a multimeter to this as well and am thinking that i could control what it monitors by some dipswitch setup or switching setup(as far as to which binding posts it's monitoring). I do understand that V = IR.  So keeping 5v but only wanting 3A, i would increase the resistance which is why at first i thought i could play a POT in the circuit.  However after seeing how the voltage regulation was hooked up, I am confused how to do so now since it was connected in the fashion i thought i would need to control the current.  (https://www.instructables.com/files/orig/F2D/LMFU/FYYNECNH/F2DLMFUFYYNECNH.jpg) I would probably use a LM338 since it would allow for more current but again, i would love to be able to have the full 50A available all at one shot but i don't think those IC's allow for that. I am extremely new to all of this and am still learning as well, so if i was able to communicate what i am looking to do correctly and you have a way of explaining it to me, a picture would be awesome if you have the time to create one. :D TYIA for any suggestions.

Posted by agentc0re 7 years ago

### Electrolysis

What is it that affects the speed of electrolysis amperage or voltage? How much of it would I need to electrolyze 100 gallons in a reasonable amount of time?

Posted by Riley C 11 years ago

### Easiest low voltage cutoff (ensure minimum startup amperage for solar fan project.)

So, if I weren't so electronically derped, I'd know this. I've seen a few easy ideas for a 12v solar fan.  Basically stick a capacitor on it. However, I'm trying to work from a few low amperage panels (~100ma@12v total).  Since I want this to keep my tent feeling cooler once the sun comes up, I don't want to be stuck for an hour or two in the morning until the minimum amperage comes out of the panels. Anyone have an easy idea of what I could use with simple parts from scavenge boards or electronics teaching kits to make it have a low voltage cutoff (so that it won't go to the fan until it hits a minimum voltage on the capacitor (so that it has a minimum startup amperage))  That way, even in the morning, at least it would pulse on for small whiles even when it didn't have enough power.

Posted by TheRevJester 5 years ago

### AC Adapter - wrong amperage?

My dvd player's ac adapter died, and while your forum on opening it up to fix it was great, it is not a simple short that can be soldered. This is a basic electronics 101 question. The old adapter put out 9v 2.2 a. I have an adapter that puts out 9v 3.0a that fits. Will I fry the dvd player by trying it out? or will it only take what it needs? Thanks for your advice. JB

Posted by jaybesq 9 years ago

### Controlling Amperage

Hiyas, I was wondering if you could point me in the right direction. I was wanting to build or buy something I could control Amp input. The system would be 12 -14 v dc and I want to be able to limit the input to say... 25 - 30 amps. So if a system would naturally draw more amps I want to be able to control the system be limiting the amp input...if that is making any sense. Got any thoughts ??? tks Huchleberry

Posted by huchleberry 10 years ago

### Control Amperage

Hiyas, I was wondering if you could point me in the right direction. I was wanting to build or buy something I could control Amp input. The system would be 12 -14 v dc and I want to be able to limit the input to say... 25 - 30 amps. So if a system would naturally draw more amps I want to be able to control the system be limiting the amp input...if that is making any sense. Got any thoughts ??? tks Huchleberry

Posted by huchleberry 10 years ago

### Multiple drills sharing a single power source

Would it be possible to run multiple cordless drills off the same power source? I do not want to run the drills all at once, but rather have them share the power source. I was thinking of modifying an ac adapter with a voltage and amperage less than the tolerances of the drill. Are there any safety concerns? If I do this will I blow myself up? Could I run them at a higher voltage/amperage? Is this idea dangerous and stupid or just stupid?

Posted by ehudwill 6 years ago

### CONVERTING A 14.4 CORDLESS PORTER CABLE DRILL TO CORDED

I am dumb today, Im also busy. best power supply for converting a cordless drill to corded would be the battery charger? or not? 6.5 amp 14.4 volt porter cable drill - model 877 charger reads 12v/14.4v 1.8 amp charger My math and logic tells me I am going to need roughyl 3 times the amperage to power this focker to full go, and that I should locate another higher amperage dealy, like a car batter charger or something....

Posted by 666mph 9 years ago

### AA Battery replacement

Hi, So I have a AA battery pack inverter for some EL wire, and I was wondering if it was possible to replace the AA battery's with a lithium Ion battery to reduce its size. What kind of voltage should I look for/do I need to take into account amperage?

Posted by Fozzibehr 4 years ago

### Voltage Control: 20v DC

I am trying to find an electronic part that will take in anywhere between 12-36v and put out a consistent 20v. What could do this? And how can I get one? If amperage matters, I'll probably be putting between 1 and 4 amps through it.

Posted by V-Man737 10 years ago

### Ohm's law?

So, i have a broken soldering iron, and i want to fix itcan someone =smart= calculate the required resistance of wire at 120v aci don't care about the amperage, as long as its under 2 ampsplease give me a range of resistance, i don't like to trip fuses, (my parents hate that!)

Posted by Sandisk1duo 10 years ago

### LED Belt

Would 4x AA batteries, light up 9 LED's in Parallel?(With a resistor of course) The LED's are 3 volt. I am making an LED belt for my Friend. I wired it up and only the red LED's lit up for some reason.( The colors used are red, green, and 1 blue) is there a problem in amperage or is there a short or something?

Posted by Jordo 10 years ago

### SMPS formulas?

Are there any switched mode power supply formulas? I've been googling but I can't find anything... I need to know relation between duty cycle (I'm using square waves) frequency size (value) of the inductor output voltage output amperage how many amps should the inductor be rated for (is it how much your drawing?)

Posted by guyfrom7up 9 years ago

### Batteries

I have a small solar set-up and was about to wire in a second battery and increase my available amperage. I just read an article about only connecting batteries of equal power, voltage (which I understand) and AH (which I was surprised). I hadn't realized that AH may also play a part in this. Can someone tell me if this is true? I have 2 older marine batteries and I change over the wires from the charge controller to recharge them separately. My thought was to wire them in parallel, let them charge together and increase my amperage at the same time. First one is 12 vdc / 80AH 2nd one is 12vdc / 60 AH I also have a 12 vdc / 160 AH that will be coming out of the boat soon and was hoping to hook that in as well (once I pick-up another panel).

Posted by olddawg 9 years ago

### Voltage regulator for solar panel

I have built a solar panel as a fun little project, now it has come upon a big problem. The solar cells that I am using seem to have a higher amperage output and a lower voltage output in high intensity sun while having a high voltage and low amperage output in medium and low intensity sun. This poses a problem as my batteries were able to recharge during late winter and early spring but now are not able to recharge when there is the most energy to be captured during the summer. The average voltage during high intensity is about 11 while the voltage during medium or low is around 12.5 and 13. I want to know if there is a way to create a transformer to step up the voltage or create a voltage regulator that can withstand 13 amps so the battery can recharge properly. A link or any suggestions would help.

Posted by menace 9 years ago

### Electronics

I am currently building an RC hovercraft, I plan to use a single 12 volt 2.1 amp hr lead acid battery to feed both the lift fan for the skirt and the power motor for the drive. However the fan for the skirt is 12v 0.3 amps. How can I reduce the feed to the required amperage with out affecting the other feed from the same battery that will power the drive

Posted by Seafarer77 3 years ago

### Scanner inverter outputs

I've just been wondering about the output of scanner inverters for a few projects, what kind of voltages and amperages are they outputting. I have a few little ideas but don't really know that much about their outputs, I gave googling and parts numbers a go but mostly found unrelated pages or had no luck with part numbers...

Posted by killerjackalope 10 years ago

### AC MOT Welder Voltage Issue

Hello everyone, I've been working on an arc welder based on instructables like https://www.instructables.com/id/Small-110-volt-arc-welder-NYDG/ but I need some advice. Most tutorials on here suggest two paths to success, either winding two MOTs with as much 10 gauge wire as possible, hoping that the voltage output in series will be close enough to 40V, or using multiple small transformers, also in series. The problem is, all this series stuff really cuts down on the available amperage, so I'm wondering if there's a different way to get high amps and volts simultaneously (obviously without surpassing the available 2400 Watts, energy in = energy out). I think I have a way to make two MOTs which run at low voltage but high amperage also have high voltage. I've made a high frequency circuit to assist in starting an arc, which you can see attached (it works phenomenally, and I've been able to make it run on 1 amp). Since the output on the HF part goes through a torroid at the far right (where it meets the welder's output), would it be possible to wind the torroid with, say, 5:20 turns, to basically take the 120A (10.8V) I get from the parallel-connected MOT transformers and overlay a low-amperage but higher voltage on it, to make arc start/run easier? The welder just won't run at 10.8v, so other than rewinding the secondaries, what about jumping the voltage up a little via the output torroid?

Posted by reakter 5 years ago

### What's up with Amps, voltage and current?

So I'm having trouble finding out where amps come in. Typical batteries (AAA,AA,9v,3v) don't say the output amps, just output voltage. But things like RC batteries, and wall transformers have a specific amperage output. So say my LED and 9v battery. I know I need to use a 150 ohm resistor. Since resistors limit current, then is there still 9v going to my LED its just the amps/current that being lowered before going into the LED? If resistors limit current, or in its unit of measure, amps, then my LED is still getting the supplied voltage just a lowered amperage?  How do I know how many amps my projects are drawing? How will I know if my DC wall transformer with 12vDC and 1 ma isn't going to fry my circuit? How would I know if 1 amp is too much or not enough for any my circuit? Please help, none of this makes sense, ~electricloser

Posted by HavocRC 5 years ago

### 12v solar panel/battery setup project- NOT lead/acid

Posted by Cking0987 1 year ago

### WANTED: Bluetooth Bee to Unlock car (or anything for that matter)

I have an Arduino uno, A  relay shield with both 4 onboard relays and an Xbee socket with a Bluetooth Bee plugged in. I need the code to: What I want is to be a able to pair my phone with the Arduino, and after that whenever it detects my phone (or whatever, just a device that has been paired previously) it will do 2 things. 1 is send a low voltage, low amperage momentary ground via relay 1, and 2 send the same via relay 2 to another device (this one would be 12v) Now when it becomes Unpaired it will wait a variable amount of time (Say 20 seconds) and then send another low voltage low amperage ground pulse via relay 3, and repeat the 12V ground pulse via relay 2 again. After that it will repeat the process from the beginning.  Im willing to Pay a Modest fee for this, and afterwards Im going to make an Instructable for anyone wanting to do the same..... and the code will be made freely available for all. Thank you for your consideration. wbarfels@gmail.com

Posted by wbarfels 6 years ago

### Need help! Arduino + Bluetooth bee + Relay shield with Bee socket = keyless enty for your car (or whatever)

I have an Arduino uno, A  relay shield with both 4 onboard relays and an Xbee socket with a Bluetooth Bee plugged in. I need the code to: What I want is to be a able to pair my phone with the Arduino, and after that whenever it detects my phone (or whatever, just a device that has been paired previously) it will do 2 things. 1 is send a low voltage, low amperage momentary ground via relay 1, and 2 send the same via relay 2 to another device (this one would be 12v) Now when it becomes Unpaired it will wait a variable amount of time (Say 20 seconds) and then send another low voltage low amperage ground pulse via relay 3, and repeat the 12V ground pulse via relay 2 again. After that it will repeat the process from the beginning. Im willing to Pay a Modest fee for this, and afterwards Im going to make an Instructable for anyone wanting to do the same..... and the code will be made freely available for all. Thank you for your consideration. wbarfels@gmail.com

Posted by wbarfels 6 years ago

### Retrofitting a battery pack into an ebike.

Ok I was just looking at this ible. And noticed the type of battery the guy used.  So I did some googling and ended up here. Wondering to myself about trying to retrofit this type of battery into a veloteq challenger from 2008 or so. Remembering that its a 48 volt pack built from 4x 12volt lead acid 20amp batteries(cells) wired in series thus to stack the voltage and not the amperage.   Now I know amperage is simply a measurement of consumption so I'm guessing that these Yellowtops are way above the usual 20amp's that the veloteq asks for but I'd imagine that shouldn't make much of a difference.  Seeing as I only want to throw on two of these as to not blow way past  the weight restriction on the ebike itself by hitting 48 volts with four of these also to avoid breaking the bank with an 800\$ purchase.  Could I not add some sort of transformer to step up the voltage to 48 volts or something like this? Any suggestions are welcome but I can't imagine this would really be all that bad of an idea.  I'd imagine it should boost the range somewhat if not a fair bit.  I'd imagine that my assumptions here are not far off but I'm here to either be validated or corrected. Or even educated if someone has any suggestions or advice.

Posted by chamunks 5 years ago

### Amps for 12 volt tire inflation pump

I'm trying to attach an AC adapter to a 12-volt tire inflation pump (the kind that plugs into your car's cigarette lighter), then convert it into a vacuum pump for degassing molds. I tried connecting the only 12 volt wall wart I have and it just barely got the motor moving. I'm guessing that the amperage of the adapter is too low. What sort of amps would this unit need to run correctly? Is it even possible to run this thing from a wall outlet?

Posted by Boy Genius 5 years ago

### How do I regulate voltage on a multi-amp battery charger.

I know very little about electronics. I have a car battery charger that outputs in 12 voltsDC. It is also "switch" selectible for 2 or 10 or 50 Amps. Once I select one of these choices 2/10/50, I would like to vary the voltage up and down from 1v to 12v. How do I build something that will vary the voltage at each of these amperage levels. Thanks- Steve

Posted by st600r 11 months ago

### Transistor help

I got a 5M LED Light Strip. Its controller say it needs 12V 2A but each LED uses 20mA each and there are 300 in this strip which = 6A. I want to cut this strip into 4 segments and power each one using an arduino. 1 strip = 2.1A 2 strip = 1.26A 3 strip = 1.5A 4 strip = 1.14A =6A My question is do I need different transistors for each strip because of the difference in amperage or can I use the same one? If so, which one!? Thanks for your attentions. Bobbay

Posted by Tzla 6 years ago

### How to regulate amprage for a combat robot

Hi everyone I am currently in the process of designing a combat robot with a max weight limit of 250lbs. the current drivetrain motors that I am using need 200 amps minimum to move the robot if fully loaded to 250lbs. The max stall amperage the motor will draw (when the stall torque is reached) is 856 amps I can not currently find an electronic speed controller that can safely handle that many amps or is in my price range. So my thought was to buy a 300-400 amp ESC and then set up an amperage regulator so that if the motor stalls and asks the ESC for more then 300-400 amps (whichever I decide to buy) when it asks the battery for that many amps the regulator will either block the current or only allow a safe amount of amps to the speed controller. I'm very new to detailed electrical side of this stuff so I don't know what exactly I'm looking for or where to find it. I would use a fuse but if the fuse blows in the middle of a match then I cant move which will cause me to lose by KO so what ever I do it must limit how many amps the speed controller can draw from the battery and then after it no longer asks for that many amps it allows it to function as normal. Thanks Guys!!

Posted by CalebP5 3 years ago

I have a Horizon T101-04 treadmill that has a control problem. The motor is definitely good. I suspect that the motor control board is good, and the control panel board is bad. The control will not reset or go into diagnostic mode. I want to replace either the control panel board or the entire control system. The motor is 90V DC. For amperage, the motor label says "19A S6 25%" which has no meaning that I understand, other than perhaps that the maximum amperage is 19. The label says "APMS" rather than "AMPS", and I wonder if the "S6" is supposed to be "SC" for "stall current." All of the characters on the label are very legible. To replace the entire set of controls, I can use an industrial DC motor control, but how much horsepower does the control actually need to be able to provide? I don't think that the one on the treadmill actually provides 19A, and is probably close to 1 HP or so in its capability.  To replace the control panel with something else and keep the existing motor control, what do I need? Do I need some type of complex driver circuit? Does it need feed back from tach sensor to do a good job of keeping the speed steady?  If it will work well, I want a simple control set up like a KB Electronics KBMD-240D to which I will add a safety cut-off switch with a lanyard.

Posted by Ineedacircuit 2 years ago

I recently bought a couple LED strips from a website, the technical info stated that the strips are ready to go on a 12v AC adapter. I found out I need 160mA to power the small strips I bought; (90 mA for one, 70mA for the other). I'd rather use batteries though, is this possible? I figure since I don't need hardly any amperage then it shouldn't be an issue but I haven't been able to find the right information to prove my thought correct. Thanks in advance.

Posted by L3fty 6 years ago

### 6v dc flourescent lamp from 12v source.

I have a left over Coleman dual florescent bulb set up from an old lantern that has several problems. The lights work and I want to hard wire it into our camper to run on our 12v dc back up. The current lamp setup is 2 6v, 6 watt bulbs. I know I can run them in series to accommodate for the extra voltage but do I need to worry about amperage? Do I need a resistor and if so, what wattage? Am I missing something else important? Thanks.

Posted by defiant1 10 years ago

### Why don't AC adapters fry?

I tore open an AC adapter to find out what I was doing wrong in my own power supply attempts. Before any other components, and connected directly to the outlet prongs, was a transformer. I know that it drops voltage and (by ohm's law) the amperage as well. But how does its survive the process? Why doesn't it have huge amounts of waste heat the way a current limiting resistor does? Why doesn't the primary coil of the transformer--effectively a tiny wire short circuiting an AC outlet--burn up? I'm certain this has something to do with the impedance of an inductor, but I just can't figure out what!

Posted by TheCorsairMalack 2 years ago

### RGB Potentiometer help!

Hey guys and girls, I've got a question! I've got 3 voltage regulators set up in parallel, wired to output 3.27V @ an amperage that I don't know (for some reason I can't get a reading on my e-meter) Anyway, The outputs from those 3 regulators are going to 3 pots, which in turn go to a set of 3 LEDs, 9 in total (3R 3G and 3B). My problem is that those pots have a max resistance of 2k ohms, and that the LEDs aren't shutting off when the resistance is maxed out. Can you guys find a way to make the LEDs shut off, yet still go on at full blast when the Pots are open? Thanks, -Josh

Posted by T3h_Muffinator 11 years ago

### Replace r/c batteries

Hi, does anyone know how to replace r/c car batteries with normal AA cells (or pp3 or whatever)? This is really annoying me coz I have an old r/c car (pretty good one actually) but the battery has died and I was wondering how to replace it (or 'refresh' it if this is possible, which I don't think it is...). It would also be helpful to know a technique for finding out the voltage/amperage of the old batteries so I can fix it without blowing the electronics. Pictures would be attached but the uploader isn't working right now; I'll get them up as soon as possible. Thanks guys,

Posted by TurboSnail 6 years ago

### Solar Ipod, cellphone charger

Hey guys I found this tutorial for building a Solar Ipod charger http://yosemiteoutside.com/m/Blogs/02EA4A6B-8893-4F3E-87A8-C1E4B24C3AAB.htmlI have already looked up all the parts for it, but when reading the data sheet for the regulator http://www.st.com/stonline/books/pdf/docs/2146.pdfI was rather confused, I got that it could take up to 35v, but there was no max amperage ratings. I am thinking of making one that is more efficient using a solar panel that putts out more watts, because the one he used only put out .6Watts (100ma x 6v), but the regulator can put out 2.5 watt. couldn't you hook up a larger solar panel. Thanks

Posted by John Culbertson 11 years ago

### Electricity for the challenged

I have a US plug AC/DC power adapter and need to get a European version. The specks on the adapter are input: 120VAC 60Hz 24 W and the output: 10 VDC 1400mA. I really don't have a clue as to what all these numbers mean but understand at a bare minimum I need something with a 10 VDC output. I've looked around at some shops and can find adapters that say 9v 1000mA and others that are 12v 1500mA. Do I need to get the exact voltage (I presume the v stands for volts)? What about the amperes ( I believe that mA is some increment of amperage)? Can I fudge the numbers a bit to save money and time instead of trying to get the exact configuration of the original adapter? Thanks for any help in clarifying this for me.

Posted by Crackpot 10 years ago

### Thermodynamics for Highschool

So, I work at a science center and we have our annual Engineering Olympics coming up and we've been brainstorming something about thermodynamics. The general format is 6 teams from different highschools in the area are given a task to complete from one engineering discipline, such as construct windmill blades to achieve the highest amperage from an attatched motor or insullate a container of water with random materials to prevent it heating up when submerged in boiling water. This year, I haven't really found an idea for thermo that really excites me. Thermo isn't the easiest thing in the world in highschool, and since we're dealing with kids from different schools, we have no way of knowing how advanced they are. So, any ideas of a project to test their thermodynamic mettle?

Posted by Dinkum Thinkum 9 years ago

### need new or used SCR for induction furnes!

Need new or used SCR for induction furnes! please any one who can help me! i need an SCR (Thyristor) , i dont care if its used or unused, i just cant justify the cost of a new one till i can be sure it will work; look at the picture below, iam replaceing the spark gap with an SCR. I put a drawing of a tesla coil diagram to compare with a simple spark gap induction drawing. \$5 to \$10 is in my price range till i know it will work. (voltage or amperage doesnt matter i would just like to see what there capable or if i can make it work for an induction furnes.)

Posted by Danielro10 9 years ago