DC Polarity Shifter / changer

Require assistance to build a device to change the polarity of 13-14 volts 30 amps with an adjustable timer. Any help would be appreciated.

Posted by NickMac 9 years ago

Polarity on speakers? Answered

I have about a dozen little 4-8 ohm speakers out of toys and alarm clocks. I noticed that while most of them have no markings, one of them has a little plus and minus polarity markers on it. Does polarity matter on cheap speakers, and if so, why?

Asked by Michael_Bell 6 years ago

polarity tester

Hi, if someone can help me how to construct such a tool polarity tester http://g-ecx.images-amazon.com/images/G/01/stores/auto/detail-page/B000KPQ7DO.03.lg.jpg Thank you in advance for helping

Posted by is4neno2 5 years ago

On capacitors and polarity.

(Asked twice already, but for some reason was not visible.) That is sort of a blanket question. I'm wondering: 1) why only some, and not all or none? 2) what (in their physical structure) causes them to have polarity? 3) why do we make ones that have polarity? Is there something prohibitive, like cost, or safety, making it so in the production? (okay, not safety, as may attest anyone who has seen a reversed capacitor explode.)

Asked by V-Man737 8 years ago

Switch electric polarity back and forth at least several times per minute?

I've seen a polarity inverter switch, but is there an automated version of one available that would switch the polarity continuously back and forth without needing to do it manually? Thanks

Asked by nlogic 7 months ago

Is The Insulated Wire In An RCA Cable, The Negative or the Positive One?

I was just trying to build an RCA to USB cable but I am not being able to find the polarities! Please HELP!

Asked by mraghib 5 years ago

How to wire a reverse polarity switch

I have an old Rascal 600 scooter that has a seat actuator that will go up but not down. I have tried to find the problem but can't.  It will operate up and down early in the morning when it is cool but later after it warms up it will only go up. I want to wire a reverse polarity switch directly from the 23VDC system(2-12 volt batteries)to the actuator motor. The actuator motor is 24VDC 12.5 AMP. It has a compression load of 600LBS. The motor has a black and red lead. Please include the size or sizes of wire I will need.  Also please be as specific and simple as possible. A drawing would be especially helpful. Thanks a million and God Bless!

Posted by themanpan68 5 years ago

how can i get a 12v motor to automatically reverse polarity or direction either by a certain time or by ???

I have a machine that is for hunting that swims duck decoys back and forth.  See youtube video " home made wake maker " but right now i  have to swith the direction automatically and i need something that i can just turn on and let the decoys swim back and forth without me touching anything.  Anyone have any suggestions?  The motor is a 12v trolling  motor with simple pulley on the top and wires are ran all the way to a box where i have a on and off swith and a switch that reverses the polarity!

Asked by stumpman42 6 years ago

4 pins with unknown polarity, i want to charge a battery with it?

So I have 4 pins with unknown polarity, and a rechargeable battery with 2 pin with known polarity, and i got a multimeter. How am i going to solve this? I randomly did something and it worked, but it did not charge, but it could use the battery, but now its empty it cant anymore. layout used is --++ please help :)

Asked by lhu 6 years ago

Polarity of tantalum capacitors

Howdy all, Recently got back into basic electronics and have started building kits. Been building a kit that uses tantalum capacitors and it notes that polarity orientation is very important. The question I have is: is there some un-published indicator of how polarity is indicated on these tantalum caps? I've been over these things with a microscope, even bought new ones, but other than the values & manufacturer, I can find no obvious sign of polarity. Leads are the same length and not marked. What am I missing? Thanks in advance for any help. Dave

Posted by gutbucket 6 years ago

n channel jfet

Can someone show me how to hook up an n-channel jfet transistor? My power supply is +5volts. Where do I hook up the load. I know the gate has to be negative relitive to the source( the source and the drain can be used interchangably, right), but I only have a positive power supply. I want to use an n-channel jfet because it normall conduct, right?I found this website:http://www.allaboutcircuits.com/vol_3/chpt_5/1.htmlbut I don't get it entireleyI am thiisss close to understanding how to use transistors!

Posted by guyfrom7up 10 years ago

Do I need a diode? Answered

I am wiring 8x 5 mw lasers in parallel, powered by a 3.7v Li-Ion rechargeable battery. I was told that I would need a diode, specifically a 1n4001 diode to regulate polarity. I know what a diode does in theory (control the direction of electron flow), but I'm not 100% where in the circuit the diode needs to go. I'm assuming it goes between the positive battery lead and the output devices. Can someone clarify?

Asked by h4xs4w 6 years ago

Why do some capacitors have polarity? Answered

(Asked once already, but for some reason was not visible.) That is sort of a blanket question. I'm wondering: 1) why only some, and not all or none? 2) what (in their physical structure) causes them to have polarity? 3) why do we make ones that have polarity? Is there something prohibitive, like cost, or safety, making it so in the production? (okay, not safety, as may attest anyone who has seen a reversed capacitor explode.)

Asked by V-Man737 8 years ago


What are the advantages/dis-advantages of using a polarized vs. a non-polarized capacitor?

Asked by jeffoloew 1 year ago

How to reverse polarity digitally (with software) ?

I would like to get a DC motor to spin in one direction for a specific number of rotations and then spin in the opposite direction for the same amount of rotations and continue to do this automatically? I know that changing the direction of the motor is achieved by reversing the polarity from the power supply, but how can this be done without using a switch or potentiometer or any other piece of hardware? I am new to this stuff so any help is much appreciated. Thanks

Asked by luch 9 years ago

Non polarize capacitors?

I would like to know two polarize capacitors joining negative to negative whether can be use as a non polarize capacitor. Thanks.

Asked by tuanb 8 years ago

Is it possible to polarize a laser pointer?

Would it be possible to polarize a laser pointer and still have it retain it's usefulness?

Asked by karate5662 8 years ago

Polarized Lights and Laptops

I was taking apart a laptop's LCD screen and found that sandwiched between the light source and the liquid crystal display were what appeared to be a vertical and horizontal polarized filter. Why is this? I always got the impression that LCD displays had the polarizers attached to the screen itself. Why would there be an extra set of polartization filters behind the screen? Or... am I just plain wrong in thinking the polarization is on the LCD itself? Could these be the only polarization filters? I have searched all over the internet for the answer to these questions, but I think I am just more confused. If these are extra polarization filters, the only thing I can imagine that they are doing is making the screen darker. Any ideas?

Posted by randofo 10 years ago

electronic magnet that produces enough force to lift weight

you have an unlimited power source. now is it possible to create enough force at the right "degree" that would be repelled by the earth instead of attracted.. so like a floating magnet. but its strong enough to lift large objects..... like maybe a human?

Asked by fireball9919 6 years ago

Lens Filter Question

I am fairly new to the DSLR world and I like the use of polarizer filters but is a polarizer filter still effective with a UV filter on top of it? I have it like this so I can easily rotate the polarizer filter

Asked by physics_dude 7 years ago

guitar cable polarity?

On a guitar cable what part is positive?

Asked by michoi 8 years ago

how to check the polarity of a micro oven transformer?

I have three micro oven transformer, which am using to build a tesla coil. unfortunaterly am in a state of confusion in knowing the polarity of the transformer...:-( so i need some guide to tell me how to check their polarity.....?

Asked by rinurose 6 years ago

I need help making a Polar Bear skin rug

I was wondering if anyone of you fine people could help me in the making of a Polar bear skin rug for my girlfriend for Christmas? Thanks

Posted by milonus 11 years ago

Neutron polarizer instructions? Answered

I need some kind of instructions for a Neutron polarizer or a quadrupole magnet. I need some divece to turn ions or alpha particles into electricty directly. If anyone finds something let me know please.

Asked by Tobor 2.0 7 years ago

Help to build sensor for Polar FS1C watch

Hello, I got this watch Polar FS1C as a gift, unfortunately without sensor which is necessary to collect data from heart rate. I would like to ask you, clever guys, if is it possible to (home)made cheap sensor suitable for Polar FS1C? I could not buy this sensor in Slovakia in reasonable price so I am trying last chance here, to built it on my own. Thank you for reply. Mx.

Posted by Mirio46x 4 years ago

3d printer control software

I've just finished making a 3d printer, only there is one problem, I need some software to control it. I've built a polar 3d printer, where the extruder moves around a central axis and along the radius of that axis. In other words the extruder moves about a polar coordinate system. So, I am trying to find the polar form of a Bezier curve, where I can input a set of x,y coordinates and get a polar curve connecting them.

Posted by Gene Hacker 10 years ago

invert polarity? Answered

Hey guys, please could you help me?  i trying to do external battery pack to run pedalboard with 4 effects. As far as i know Boss pedals have center negative type of connection. Can pls somebody explain what does it mean? Whether it means that leads are inverted positive goes to the sleeve and negative to the tip? Or tip has to receive negative voltage of minus9V? thanks !!!!

Asked by IgorA26 1 year ago

How can I get a filter whose color depends on the polarization angle?

Suppose you have a filter through which light linearly polarized at a 60` angle looks red, 120` looks green, and 180` looks blue. A mixture of 60` and 180` looks purple (red+blue). Unpolarized looks white (red+green+blue).Does someone make such a filter? Or one that only polarizes light in a narrow band of wavelengths and transmits other wavelengths unpolarized? Or can you think of a way to capture this information in a photo without specialized equipment or taking multiple pictures?

Asked by NobodyInParticular 9 years ago

Harbor Freight 9 LED polarity.

Https://www.instructables.com/id/Harbor-Freight-Led-Flashlight-----of-DEATH!!/I want to use that flashlight, and mod it to a different colour led but I need to know if the pbc board has polarity.

Asked by Noodle god 9 years ago

How can I reverse polarity using 2 switches?

I am trying to reverse polarity on a small 12 v pump. I currently have 2 SPDT switches and have them hooked up like a DPDT. I am getting voltage feedback when they are in the off position. I need to have t switches any help?

Asked by craigbalex 8 years ago

How do I make an Electromagnet? And a few questions about them and regular magnets?

   I’m looking to learn about electromagnets and magnets. I looked up all those common videos on YouTube of course but It’s not the same as asking people who can tell me directly how to go about making one and things I can do with them.    Here is what I know about electromagnets so far. I know that you wrap wire around a piece of iron neatly (the more times you wrap the stronger it is). Then you attach a battery to the ends of the two wires that are left and then you have a electromagnet. I also know that to much power is bad because it can heat up. I want to make some cool things with electromagnets. So here are my Questions: Center Of The Electromagnets Questions - What is the best thing to put in the center of a electromagnet? - Is Iron the best and if so what is the best type of iron to use? - If different materials will have different effects could you please list them? Wire For The Electromagnets Questions -What kind of wire works best? -Will thinner or thicker wire wrapped more times around make it stronger? -What is a good wire to iron ratio? Power For the Electromagnet Questions -Could I use a DC wall Plug instead of a battery? -If I use a wall plug could I make a separate Positive and Negative electromagnet? Few Random Questions -What materials will that block electromagnets? Which works the best? -What can you tell me about electromagnets that I didn’t ask? Thanks for reading guys hope you guys can help. I check this constantly so feel  free to pour Info in here.

Posted by Rich The Poor 6 years ago

Motor reversing? Answered

While you noted the simple manual motor contoller can't reverse the motor, couldn't a DPDT polarity reversing switch be placed downstream of the motor controller to allow the motor to be reversed? The controller still does its thing controller power to motor and the polarity reversal switch just selects which polarity goes to which side of the motor. Sure you need to let the motor coast down to a stop before reversing rotation direction.

Asked by LarryB 7 months ago

How can you tell polarity of disposable camera flash and capacitor?

Wondering how to tell positive and neg on camera flash.. and the same for capacitor.. I see the capacitor has a greyish stripe down one side.. want to just wire strait from either flash or capacitor to restore/zap batteries back to life. Do you even need to get the polarity correct for this?

Asked by burr0010 8 years ago

Gas nozzle or gas cup polarity? Answered

Is the gas nozzle or gas cup carrying any charge? Would I generate a spark of I accidentally let it touch the work piece. I have shaky hands and I'm worried about creating an arc with it.

Asked by JohnH514 1 year ago

Electromagnetism question Answered

Hi I just saw something weird, it's not an exercise or a problem but I still have a question :  Let's say we have 2 electromagnets of unequal strengths X and X+Y; between them we have a ferromagnetic bar  Let's say one has south polarity and the other one north if we change which one is stronger ex 1st is X,  2nd is X+Y than a moment after 1st is X+Y and  2nd is X the bar will have the polarity of the stronger one for a moment, right? ex for a moment the electromagnet with the south pole is stronger X + Y = the bar will become south pole than we return it to its normal strength X and make the north pole electromagnet stronger X+ Y= the bar will become north pole, right? How will such variations of the strength of the magnetic field on 1 side affect the entire device, will only the bar change its polarity and it will stop somewhere on the border of the second magnet or will the second electromagnet change it's polarity too if the first one's is very strong? (just wondering) If we fix a coil on the ferromagnetic bar will such variations in the magnetic polarities of the bar induce current in it and how much, as much as we used to produce the fields of both electromagnets or only for the field of the stronger one, or only the difference between 2? and the last question in the terms of relation between the strengths of both electromagnets (let's say in %) how much Y should be to change the polarity of the bar without affecting the polarity of the second electromagnet?  Thank you all in advance for your interest, assistance and time :)

Asked by Elys 3 years ago

How do you figure out polarity for some salvaged circuit components, like resistors, etc? Answered

I took some resistors off a board and noticed that the board said positive at one lead but I didn't pay attention so how do I figure out which is which

Asked by phillyj 9 years ago

What type of capacitor are these? Answered

Hello . I just get some non-polarized capacitor .But What type of capacitor are these? Thanks!

Asked by login721 5 years ago

why there is change in polarity in a bar magnet when it breaks?

A bar magnet when breaks does not attracts but repels from where it has broken ...   like [N-------S]   is a bar magnet on breaking it should be like  [ N---S} {N---S ] but it happens to be  [N----S} {S---N] ..  means there is "repulsion" between them WHY SO ?? (Pratically seen)

Asked by aporak 5 years ago

Diode? Answered

If I reversed the polarity of a standard sillicon diode and applied a voltage higher than what its rated for,what would happen?

Asked by MrPros101 1 year ago

Can Anybody Help me with Audio Terms?

I am on my way to build 3 way speaker system and this my first time. I heard that i have to make crossover into the speakers which will drive the low frequencies to the woofer and mid ranger whereas the low pitch to the woofer. I went to a site that calculates schematics for any sort of crossovers. But they ask me the several things out of them i understood some of them while others made my mind disrupted. so please state the meaning of the following: High Xover Frequency ( fh ) Low Xover Frequency ( fl ) Frequency Spread ( fh/fl )   here there were 2 options I.E, 8:3 octaves and 10:3.4 octaves Bandpass Gain ( g ) Crossover Type In the last one there were several options: 1st Order normal polarity 2nd order reverse polarity 3rd order reverse polarity 3rd order normal polarity 4th order normal polarity What are the differences between these crossovers? Which one is the best and why? If nothing is best so what is the difference? Sorry I am a novice. So guys please be easy on me....  Thanks In Advance :-)

Asked by adarshnarsaria 5 years ago

Does this switch exist? Answered

It may just be my google-fu failing me, but I can't find switch I am sure must exist: A sliding switch with reversing (DC) polarity. At one end of the slider, power is full "forward".  Slide the controller, and power decreases.  Reach the centre, and power is zero/off.  Slide past the centre, and power increases again, but with reversed polarity, ie in reverse.

Asked by Kiteman 6 years ago

what type of capacitor is this ? Answered

Hello , i just bougth some capacitor from electronic store.In my country ,English is not the nature language ,so i dont know what is the name of this type of capacitor in English .they have number 104( 100nF)  and other is 105(1uF).And they dont have mask witch pin is  + or  -  pin.Thay mean they are Non polarized capacitor ??  Here is the image of them . Thanks ! p/s: sorry for my bad English.

Asked by login721 6 years ago

How does this 5 pole switch work?

I took apart a broken DVD player. I wanted to possibly use the tray mechanism for a project. It appears that the DVD player uses a 5 pin pcb mounted switch to reverse polarity for the motor. I can of however figure out how to wire this and make it work. How does this 5 pin swith work to switch the polarity of the motor?

Asked by MDheliMech 5 years ago