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Questions tagged [polarity]

Polarity is a conceptual entity. Pole means a direction. However, an object is called as "having polarity" or "having specific polarity" means a preference to a differential-behavior of something in forward and backward direction.

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1answer
397 views

Identifying the polarity of the aluminium electrolytic capacitor

I have the following device - polar electrolytic capacitor (it is/was having stripe on its sleeve): I know its capacitance and voltage rating - 2.2 uF / 400 V, but accidentally removed the remainders ...
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213 views

ESD and Electrolytics

Consider the simple circuit schematic below: 1) Would a high voltage (say 1kV-25kV) human body ESD discharge event (1ns rise time, 100ns total) at OUT have a negative effect (damage or destroy) the ...
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2answers
955 views

Polarity of capacitor on PCB

I've removed a capacitor, but like the n00b I am, have forgotten which way round it went. From this picture can you deduce the polarity? It was removed from the board in the circle with the two ...
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6answers
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Determining the correct polarity of a supposedly wrong polarized capacitor

I'm fixing an audio interface (Scarlett) that was behaving poorly and found a likely culprit - a bulging capacitor. However, it appears to be soldered on the board backwards (based on the `screen on ...
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0answers
83 views

How is a power cord connector polarized?

For example, the common PC power cord cable (IEC 60320 C13). How is it polarized if you can just switch the power plug upside down (EU)? Does it have any internal circuitry?
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1answer
162 views

How to protect my DIY bench power supply from reverse polarity?

I have been playing with arrays of 18650 batteries for the last 10 months, charging and discharging them all the time with my LM338K based power supply, that, until tonight, where I inadvertently ...
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1answer
624 views

Monopolar DC transmission line: why is the preferred polarity negative and water used return path?

How and why energized conductor is of negative polarity for Monopolar link in DC transmission. And how can water be used as return path? And why negative polarity cause lesser radio interference? ...
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1answer
144 views

NPN TRANSISTOR POLARITY

i am a mechanical engineer i have a question on a transistor. what happens if i apply a +ve terminal to base and negative terminal to emitter in a NPN transistor with no wires connected to the ...
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1answer
181 views

How does the lead polarity work on a D'Arsonval galvanometer?

Following an illustration of D'Arsonval movement such as the following... I notice that the N polarized part of the coil is connected to the positive lead and the S polarized part of the coil is ...
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2answers
143 views

How can I find removable plugs for standard pin headers? [closed]

I'm making a right angle adapter for a module with a 2x10 pin layout that has one blocked. How can I find the little plastic pins to block a hole, ideally ones that are removable? I realize I could ...
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1answer
387 views

Polarized Electrolytic Capacitor - Reverse Polarization

There is one small problem in my understanding of polarized capacitors. The thing is that when using polarized capacitor, you should apply positive voltage terminal to anode and negative voltage ...
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1answer
54 views

Side effect of dielectric polarization

Sorry for my obvious question, but I am not from the field of electronics and electric engineering. I was reading this article: The first sentence in the introduction says: " All solid ...
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4answers
11k views

testing wire polarity with a multimeter [closed]

I have a power cord that is supposed to supply an appliance with 12V D/C power. The power cord has positive and negative leads. One lead has the typical writing on it which could identify it as the ...
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4answers
1k views

Using limit switches to reverse circuit polarity

I am designing a linear translation stage that will be driven with a DC motor. When the circuit is powered the DC motor will start turning in either direction, which will move the linear stage towards ...
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2answers
302 views

Capacitor polarity confusion in a circuit

I was reading about opamp integrator concept in a text as such: I marked the terminals of caps as a and b. Above formula assumes the b terminal as being the positive end I guess. But regarding the ...
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3answers
1k views

LED anvil and post are reversed!

Typically, through-hole LEDs seem to have the cathode (-) side connected to the "anvil" and the annode (+) connected to the "post" (see diagram below). ...But I now have in front of me an LED that ...
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1answer
707 views

astable multivibrator: capacitor polarization

Looking at this circuit, I'm wondering if the capacitor polarization "+" is correctly draw. Assuming T2 is in cut, T1 is on, left capacitor will have a 0.7v in its right side (connected to T1 emitter) ...
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1answer
1k views

How to tell the polarity of a power adapter's wires

I purchased a power adapter so that I could put a different plug on it, but when I cut the wire and stripped it, it didn't have a colored jacket on it. The brick does not have a diagram on it, so I ...
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2answers
332 views

Solid state relay (SSR) - alternating polarity

I'd like to control a slave clock, via a relay(s), which needs an alternating polarity pulse once a second. The attached circuit incorporates two SPDT relays which do this (one relay activated one ...
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0answers
336 views

AC L+ and N- difference

Hey guys i'm on a project in which I have to use Safety Modules. I'm confused with the pin-out diagram of the safety modules. They reference L and N lines of an AC source. I'm leaving you the data-...
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3answers
639 views

Confused about polarity of Transformer

I am confused about the Transformer dot polarity. I got design from ST's edesign Suite. Here is schematic for that :- Now I need to order the design for transformer and the transformer design centre ...
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1answer
7k views

How to determine the electrolytic capacitor polarity from PCB printings?

I have this PCB board that I need to solder a capacitor to it. This is the board: And I'm not sure where should I solder the negative and where the positive. Can someone please explain what this ...
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1answer
2k views

Voltage Divider to protect P-FET gate on a Polarity Inversion Circuit

I'm trying to implement a polarity protection using the P-MOSFET technique on a 30v DC circuit How can I protect the gate of a IRF9540N (Vgs 20v)? I saw that I can use a voltage divider using 2 ...
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2answers
170 views

Are there circuits to ensure polarity with symmetrical and unpolarised AC plugs?

There are many different connection systems (socket,plug) which are symmetrical and unpolarised such as The Schuko connection system is symmetrical and unpolarised in its design, allowing line ...
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3answers
4k views

Does reversing polarity in AC damage the equipment? (Sonoff Wifi Switch) [closed]

Firstly, I am a beginner. Excuse me if this is a dumb question. I have ordered a Wi-Fi switch named Sonoff. I have a doubt whether the device will work if the polarity is reversed or will it get ...
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1answer
4k views

Polarity symbols on universal AC-DC adaptor

I have a universal AC-DC adaptor that has the following symbol by the polarity switch: Is it safe to assume that the top part of the diagram indicates the polarity of the inner surface of the ...
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3answers
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What does the radiation from an antenna look like?

Just out of curiosity, I searched for antenna on Google Images, and what usually shows is something like this. So I really thought that an antenna radiates in a circular and equal pattern. But as I ...
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1answer
9k views

Troubleshooting why Powerbank Doesn't Charge Cell Phone [closed]

I have powerbank that provides 5v (presumably regulated) power, as typical of most usb interface powerbanks. I have been trying out my powerbank with different phones. It works on all except one. I ...
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1answer
637 views

Preventing reverse polairty in NiMH batteries

So, I am powering The Device. It's low power, running at <10mA. Minimum voltage required is 3.5V, so using NiMH rechargeable batteries you need 4 in series. My problem is that they discharge, ...
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2answers
162 views

Both pins of my schuko sockets live? [closed]

I would appreciate any help anyone is able to give me on this. I live in Spain and I am trying to check the polarity of a wall socket where I plan to plug in a extension block with all the various ...
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0answers
122 views

polarity of unmarked battery with zero charge

This battery has the following equivalent part numbers HMA2104, HTPA7W, BKB191210/4, but I cannot find any information on the polarity/pinout of the 3 pins. Is there some safe way to figure out the ...
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1answer
64 views

Identifying the capacitor polarity from a Samsung 2333SW LCD Monitor [closed]

There are no marks on the sides or the bottom, Only the top is marked by a half moon.(See Picture) How do I determine the negative side of the capacitor. wires on the bottom come from the half moon ...
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2answers
85 views

Using single LED as bipolar DC detector

It would be very handy for me to have an XLR plug with an LED on the end to check for DC at the output of balanced audio gear. The challenge is two fold. First is that this gear can fail with a ...
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0answers
2k views

How can I add N channel MOSFET for reverse polarity protection?

I would like to add a reverse polarity protection circuit to protect my circuit from reverse polarity. I tried to use following circuit at this link With NMOS FET, I have a little problem. If the ...
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2answers
2k views

Which symbol to use for polarized capacitor?

Ok guys, this has been driving me crazy and I would love an absolute universal answer (even though I know there are disputes)... Which symbol should I use for a polarized capacitor? At school they ...
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1answer
694 views

Polarity of of capacitors

I understand that similar questions have already been asked but haven't been able to apply them on my problem. I am working on Double integrator circuit as below (to simulate a physical system for my ...
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1answer
4k views

Packaging polarity indication of a supercapacitor (polarity indicated by arrows)

I obtained some supercaps from an auction site. As is often the case for low cost components from such sources, these do not have supplied data and such branding as there is does not appear traceable. ...
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1answer
240 views

How do LCD displays with passive 3D polarize light?

I understand how this works with projectors but I cant find any explanation for LCD displays. From what I understand 2 images are interlaced and displayed at the same time. How is it possible that 2 ...
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1answer
82 views

Circuit for controlling AC signal polarity in real-time

I'm going to start a project on a controlling speaker array and I need to control the signal's polarity fed into each speaker. I want to make a 'router' or 'controller' to make it easy, so I don't ...
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4answers
424 views

Rapid Reverse polarity

This is the circuit for reverse voltage protection, R2 is the load of a motor. The problem is that there is a test where the changing of polarity is very fast ( <5ms) and the MOS burns. Power ...
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3answers
956 views

What circuit will allow reverse polarity and continue to work?

I am looking for a circuit that will power my device with 12-24v no matter the polarity, the device will use around 1a maximum. I know a bridge rectifier should work but I cannot deal with the ...
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2answers
99 views

Polar capacitors and a lack of jargon

Today I found myself wondering something about capacitors, and though my first reaction was to turn to Google, I also discovered that I don't know how to word my inquiry without getting ten thousand ...
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7answers
13k views

How to memorize a diode's polarity in symbol? (self-answered)

How to memorize a diode's polarity, such as anode and cathode in symbol?
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1answer
3k views

Is the PWM rail of a 4pin pwm Computer fan Positive or negative

I am wiring a 4 pin computer fan to a 12v dc power source and I am wondering the pin for the PWM is positive or negative.
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2answers
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Can current flow both ways through a transistor?

Last night I was experimenting with and motors and transistors. I was testing out NPN and PNP transistors to learn more about how they work and how I can use microcontrollers to control the speed with ...
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1answer
608 views

rx_polarity inversion in USB3.x

As per USB3.x specification there is provision of rx_polarity_inversion can any one exactly says, what is the reason behind it? Edit: Normally connection of ...
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0answers
2k views

Don't reversible 2 prong plugs have to account for orientation?

I don't know much about electrical hardware, so forgive any naivety. Anyways, I've been wondering: since 2 prong plugs (the reversible ones whose prongs are the same size) can be plugged into a ...
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4answers
12k views

Confusion about dot convention in an ideal transformer

I am confused about voltage polarity and current direction in transformers , for example the equivalent circuit of the ideal transformer in figure(a) the instantaneous voltage polarity of the ...
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2answers
824 views

Why is the voltage more in case of same polarity during a polarity test of induction motor?

I was performing experiment in the lab of my university. The experiment was supposed to be performed on a squirrel cage induction motor. But I performed it on a three phase slip ring I.M with its ...
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3answers
637 views

What do you call a device that reverses polarity?

I am replacing a DC power supply used in a lab experiment. We need to be able to choose a positive or negative current. Bipolar power supplies in our power range (around 1 kW) are expensive, so I am ...