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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69 views

Reverse polarity protection using back to back NMOS

Designing a circuit to measure short circuit current of a power supply every second. Measurement will be on for about 50ms every second. Heat design has been made for this about of time not constant ...
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37 views

Insulate active or neutral?

If you can only insulate active or neutral, which should you choose? Does it matter? Is it important? Is one better than the other?
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44 views

Switching polarised capacitors in a guitar effects pedal

I'm building a basic guitar distortion pedal, the Two-Transistor Fuzztone from the book Snip, Burn, Solder, Shred. I want to add a multi-throw rotary switch to select between input capacitors, and so ...
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2answers
49 views

Invert polarity with DPDT relay

I'm trying to wire a 12v DC motor to a DPDT switch so I can control the spin direction (by inverting the polarity) it uses two digital pins, one of them to set the direction of the motor and another ...
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109 views

How can a battery get reverse charged? (other than by being charged backwards)

I have an old lead-acid car battery that got taken out of my car by AAA 5-10 years ago when it died during a cold winter. I stashed the battery away and forgot about it. Recently I dusted it off and ...
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1answer
26 views

Driving piezo scanner tubes using the driven internal electrode configuration

I'm planning on doing a project involving a piezo tube scanner (PTS). The PTS will be used for 3 axis manipulation of a sharp needle. PiezoDrive has a few scanners and some info on how to use them. ...
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42 views

High voltage power supply polarity for X-ray tube application

High voltage power supplies (HVPS) in the range 100 to 200 kV are used for working with X-ray tube. Some HVPS produce negative output voltage or even bipolar output including negative and positive ...
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4answers
157 views

Voltage induced accross an inductor, conceptual confusions

simulate this circuit – Schematic created using CircuitLab OK, I always have a hard time to understand inductors. Now, I do know that inductors will not let current through them to change ...
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31 views

LTC7001 Mosfet Driver is not working because of DPDT Relay

I am using a mosfet driver(LTC7001) to drive a mosfet. The mosfet is conducting 28 V continously which means its driver is always open. In a step I must reverse polarity of load by using a DPDT relay....
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47 views

Finding out capacitor polarity on pcb

I made the quintessential newbie mistake: I removed 2 capacitors (CF07/CF08) without noting down the original lead position. The interesting part is that the schematic (attached) seems to convey that ...
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108 views

Capacitor put the wrong way by manufacturer - is this on purpose or is this a problem?

I am about to change the electrolytic capacitors of a Soviet Selena radio from 1988. I noticed that a few of the capacitors are put with the oposite polarization in respect to the board, e.g. this one ...
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102 views

When is a non-polarized electrolytic capacitor inappropriate?

I am recapping a vintage power supply and I've done similar before but I'm a hobbyist non-expert. My understanding has always been that using a non-polarized cap is acceptable where an polarized ...
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35 views

DPDT switch to control DPDT relay

this is a bit of a long shot but here goes. I need to buy a speed controller for an electric ride on car and I've had no success in finding one with a reverse polarity switch and one that also ...
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36 views

What's the difference between polarization ratio ρ_C and ρ_L?

I have the following 2 equations in my textbook: ρ_L = E_Φ/E_θ ρ_C = E_R/E_L = (1 + jρ_L)/(1 - jρ_L) Both ρ_L and ρ_C are called polarization ratio. However, what's the difference between the two?...
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Puzzle: diode polarity in a vintage tachometer circuit

Once again, I'm trying to reverse engineer an old tachometer circuit--1970s vintage this time. There are three diodes on the circuit board, and two have absolutely no markings whatsoever. Can anyone ...
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3answers
81 views

Replace ONE 25v 47uf capacitor with FIVE 60v 10uf capacitors parallel?

MY 1000 Watt True Sine Power Inverter blew a 25V 47uf capacitor. The shell was rattling around inside, and the ribbons were exposed. Yay, I found the problem! Sooooo, how can I tell the mounting ...
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41 views

front and back LCD polarization film angles

I've taken apart an old dot matrix LCD because the polarized films are burnt. I removed the old ones and ordered a 10x10cm sheet (https://www.aliexpress.com/item/32804985320.html). I read that ...
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83 views

Maglev Train Propulsion System [closed]

So I'm trying to make a small Maglev train for a science fair project. I understand how to make the train levitate, but not how to make it move forward. When I look online, everyone explains how you ...
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40 views

Electrolytic capacitor polarity voltages

What happens if we feed an electrolytic capacitor only positive voltages while keeping the negative pin voltage lower than positive. for example positive pin 20V and negative pin 5V. Does it affect ...
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1answer
40 views

Cable wires - confirmation of live and ground

I bought a generic DC power extension cable and I'm trying to wire it to a connector with a cable attached. The connectors cable clearly has two wires - a red and black/+ and -. This is what I'm used ...
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1answer
29 views

Programmable polarity switch for DC circuit

My question concerns a future research project in electrocoagulation (water treatment) I am planning right now. I will have a lab power supply connected to two (or more) plates in water. The ...
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29 views

Parabolic wave equation, electric and magnetic field definitions

The split step solution for Parabolic Wave Equation (PWE) applied to the tropospheric propagation problem is: $$u(x+\Delta x, z)=e^{ikM(z)10^{-6}\Delta x}\mathfrak{F}^{-1}[e^{\frac{-ip^2\Delta x}{2k}}...
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79 views

Socket polarity

So recently I was installing these old fairy lights and its plug was burnt due to faulty connections, So I bought a new plug and replaced the old plug. I was wondering why do these fairy lights do not ...
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167 views

Reversed polarity of CR2025

My bike light uses two CR2032 batteries, which I replaced with CR2025 and some padding. It stopped giving light, so I removed the batteries and measured voltage. One battery gave 2.8 V, and another -1 ...
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42 views

ensuring transducer (transmitter) and receiver polarity

I am trying to implement a simple phased array of 7 transmitters rated 40 kHz. I have a few receivers to measure the acoustic field generated to validate if it works. What is a simple way to measure ...
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2answers
238 views

Can I trust in visual inspection to identify LED terminals?

In the figure above, LED A is a regular 5mm LED and the visual identification of its terminals polarity is well known. As you can see, on LED B the anode is identified by the longer leg, but the ...
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1answer
72 views

ESD Protection diode polarity

I'm using the following ESD protection diode: On the datasheet it says: MOUNTING POSITION: Any Does it mean I can assemble it at any polarity? (switch cathode and anode connections)
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144 views

Can I use this DPDT relay with this circuit? If so, which wires connect to what terminals?

I'm following this tutorial to wire an automatic chicken coop door. The DPDT relay they're using is different to my relay so I'm finding it difficult to understand which wires connect to where. I'm ...
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214 views

Phase or polarity for North America residential 240V

I understand that for North American residential, the three wires coming into the panel box are +120V,-120V, and Neutral. Is there such a thing as phase or polarity between these three wires? How is ...
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1answer
377 views

What happens if I change the polarity of the battery?

Suppose if i charge a capacitor. Now if I reverse the polarity of the battery, how much is the heat produce during that process? My book says as change in energy = 0 (in capacitor) therefore heat ...
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3answers
526 views

Switching between battery and external power sources with reverse polarity protection

In my design, I will use AA batteries to power the electronics board. As a requirement, also it should accept the power from external power supply (12V) - The board should automatically switch from ...
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1answer
59 views

How can line code polarity inversion happen?

One of the disadvantages of some line codes like NRZ-L or RZ is that if a sudden change in polarity occurs, then all received bits will be erroneous (flipped). How can such a sudden change in ...
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1answer
129 views

AC/DC Power adapter plug: difference between center positive/negative

Why are some power adapters center positive and others center negative (less common, at least around me)? Is there any compelling reason, something that asks for one or the other for different ...
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2answers
509 views

What is the polarity of this barrel plug with a double circle?

Related but doesn't answer my specific icon: How to tell polarity expected of a DC barrel jack? I have a dell laptop barral plug adapter, and I can't tell from the graphic whether the tip is positive ...
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1answer
50 views

How to rapidly switch polarity of two plates?

If I have two metal plates, with P1 connected to V+, and P2 connected to GND, how can I alternate the polarity of these two plates? I wish to have P1 connected to GND, and P2 connected to V+. Then ...
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2answers
256 views

Connect IR Emitter (+) to IR Receiver (+)?

I have a vehicle stereo deck that has an IR receiver input (+) and a steering wheel control module that has an IR emitter LED (+/-). The steering wheel control module, "translates" (using a mapping ...
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3answers
6k views

Why do we use polarized capacitors?

I want to know if the polarized capacitor has some advantage that they are used in some circuits? For example, in a schematic of the BISS001 PIR controller IC, in some places, a polarized capacitor ...
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1answer
225 views

Why is the electrolytic capacitor not polarity sensitive?

The issue I was making a project in which I had to use a 2.2uF electrolytic capacitor in series with a microphone and weirdly, the circuit works even if I toggle the polarity of the capacitor, that ...
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1answer
97 views

How do I add a bipolar stepper motor to this circuit? [closed]

I have just started electronics at school and cannot find any tutorials on how to do this. I am creating a circuit that when the light intensity increases a bipolar stepper motor will step clockwise ...
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1answer
68 views

Polarity. What do “C” & “P” signify?

G4 bi pin LED bulb. Silicone coated Hello all. Thanks for the forum. I have some of these: G4 bi pin LED bulbs. Silicone coated dimmable 12 volt DC. They are 1.5watt. Although not visible on this ...
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1answer
293 views

help understanding this reverse polarity protection circuit

Going through LT4363 evaluation kit DC2062A-B (schematic here), I came across a reverse protection circuitry that protects downstream components from reverse transients and reverse DC voltage: In ...
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2answers
125 views

Is this relay datasheet incorrect? (Omron G6SK-2)

I'm using Omron G6 series relays, both the non-latching (G6S-2) and and dual coil latching (G6SK-2) for a few PCB designs. What I didn't know was that some models of relays give their connection ...
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3answers
253 views

LEDs in computer case are non-polar?

Normally I think of LEDs being polar and having a definite current direction, the "D" in LED standing for "diode". However, in working with with a computer case recently, the front part of the case ...
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157 views

Question About Current Flow Direction [closed]

I've got a question that has been perplexing me for a while. (Correct me anytime) (Please do not give me any textbook definitions.) Starting with the name of the question itself, I believe current is ...
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1answer
180 views

Is this capacitor polarized?

I recovered a few capacitors of this style from an old cassette player. As far as I can tell, it seems like Mylar film, but the “100⊖” marking has me wondering. Is this some peculiar shaped tantalum ...
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2answers
576 views

Identifying polarity of capacitor from PCB printing

I took out the old capacitor and didn't remember to check the polarity because I assumed the board would have more standard markings. Is there any way to figure it out with a meter or by the printing?
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235 views

Is it possible for a voltage multiplier to be used to provide both positive and negative voltage?

What I was wondering is it is possible to use a single voltage multiplier to provide a negative and positive voltage. Referring to this voltage doubler circuit, if you connect a capacitor to the top ...
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1answer
65 views

Why I don't get horizontally-polarized TVs in the satellite from time to time? [closed]

Something like once every 2 days I cannot watch horizontal SAT channels for about a half day. It says "no signal". During this "no signal" time I get very rarely watchable time. Like 1 minute in an ...
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1answer
268 views

Conflict of polarity?

With the following circuit, would the R2 resistor not change or affect the polarity in some negative way (no pun intended)? In the image below I added the red box as well as the red text in an effort ...
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2answers
348 views

Which one is the positive side?

I'm newbie, thus my simple question. In the schematic below, which side of the capacitors is the positive? Why? Or are they assuming that I have to use ceramic capacitors? Usually my schematics come ...

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