Questions tagged [polarity]

For questions about polarity considerations in electronics due to circuit components with polarity (e.g., diodes, transistors, polarized capacitors, batteries, etc.), polarity of quantities directional quantities (such as currents, voltages, electromagnetic fields, etc.), polarity symbols, etc.

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Polarity negative or positive on DC barrel jack?

I have a DC port, can I make it positive or negative inside?
abu abdallah's user avatar
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25 views

Polarity Detection on Array Charging System for Autonomous Robot

Array Charging Concept I recently became interested in designing a charging system for an autonomous robot. The key requirement is that precise orientation of the robot is not necessary during ...
RemiFM's user avatar
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Do non-polarized capacitors need to be in any type of orientation?

I have submitted my PCB design to JLCPCB for population. They are asking me if the orientation of my capacitors are correct: My PCB and schematic of it: In the datasheet it states that these are non-...
StealthRT's user avatar
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4 votes
3 answers
440 views

Flyback Transformer Winding Direction

Looking at the basic Flyback Converter Topology, the coupled inductor polarity should be opposite in order for the circuit to operate properly. However, I am confused on how to implement the correct ...
Gman's user avatar
  • 101
3 votes
4 answers
506 views

Reversing the polarity on a relay

I have a single coil latching relay (HFD2/012-S-L2): + & - to set and - & + to reset. I have a 12 V supply to trigger the relay (via a push-button switch). My question is this - how to get the ...
Dave Lees's user avatar
3 votes
2 answers
479 views

Which side is the capacitor negative on this board? (IO/10 marking)

I removed a capacitor (C1 (400v/15uf) - highlighted in the picture) from this board to test on another board and now I want to put it back but I can't figure out the polarity. The traditional symbol ...
ExpectZomibesBy2020's user avatar
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2 answers
285 views

Why aren't I getting a voltage reading from my AC/DC power adapter

I am new to electrical engineering. I cut the barrel jack off the end of a 24V DC power adapter, exposing a red and white wire. I'm trying to determine the polarity of the red and white wires with a ...
A__'s user avatar
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4 votes
2 answers
991 views

Footprint for Electrolytic Capacitor

I plan on using this capacitor on my project: https://datasheet.lcsc.com/lcsc/2209011730_KNSCHA-RVT330UF50V167RV085_C5155333.pdf This is an electrolytic capacitor (this means it has polarity.). The ...
user1584421's user avatar
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1 answer
110 views

High voltage polarity inverter circuit

I'm building a cloud chamber which needs to use an high voltage source. I'm using an electric fly swatter circuit which can generate about 4kV. The fact is that I want to use a button to switch the ...
Luke__'s user avatar
  • 309
2 votes
1 answer
267 views

Does USB3.0 support reverse polarity in SSTX and SSRX?

Is it possible to Sawp the +/- pins of SSRX and SSTX to make the routing easier and avoid using vias? Does USB3.0 support this reverse polarity?
Mojtaba Najafi's user avatar
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2 answers
190 views

Lighting Christmas Village Streetlights with LEDs

I purchased a Christmas village from Walmart on sale after the holiday season (Holiday time 30 piece Mini House Set). The 5 houses take 2x AAA batteries each, but I converted them to DC plugins ...
Sloanstarr's user avatar
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1 answer
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Testing transformer polarity with a signal generator and an oscilloscope

When using the above test setup to measure transformer polarity, the output on my oscilloscope shows a flat line at 0V, it does not register the waveform from the signal generator. The output on ...
willieb3's user avatar
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1 answer
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AC polarity detection circuitry

The three wires in a marinr 120 VAC shore-power circuit are normally black for power, white for neutral, and green for ground. I’m searching for a circuit that will power an idiot-light in order to ...
brent chalmers's user avatar
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1 answer
70 views

What is the polarity of a custom power supply? [closed]

I have a custom power adapter (this one), but I do not understand what the correct polarity is, as its tip can be reversed. In the picture I have highlighted the marks in the current situation (so the ...
RDGuida's user avatar
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1 vote
3 answers
167 views

DC christmas string lights without polarity

My sister was doing an electronics project assigned from school and she was given sets of christmas light-looking bulbs in sockets with two wires sticking out of each. When she asked me for help ( it ...
chill389cc's user avatar
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3 answers
1k views

Which of these wires is positive and which is negative?

I know that in DC circuits the colour code is often (but not always) that red is positive and black is negative. On this AC mains wiring the wires are blue and brown. Does anyone know which is which? ...
Mito's user avatar
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2 answers
229 views

Can you change the polarity of a flyback transformer by swapping the output pins?

I am using the following flyback transformer from Pulse electronics: I am typically used to seeing the dots reversed on the diagram. For this transformer, would current be flowing out of pins 5, 9 ...
willieb3's user avatar
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7 votes
6 answers
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Inductor polarity

Let's say an inductor has DC current going through long enough for it to completely build it's electro magnetic field. If the source voltage then goes lower, the inductor will 'use' the energy stored ...
Charles-Ugo Brouillard's user avatar
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1 answer
264 views

Should a start-stop interrupt positive or negative? (Why?)

This answer shows a "standard" start-stop circuit. I was trying to design my own, and came up with a design that is essentially the same, except that it interrupts negative, with positive ...
Matthew's user avatar
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3 answers
627 views

How to figure out the direction of current and polarity of a circuit element?

How do I determine the direction of current in the boxed region? Also, how do I figure out the polarity of the resistor?
Sathvik R.'s user avatar
-2 votes
2 answers
4k views

Which wire is positive on this audio jack (blue and white)?

Which wire is positive and which is negative on an audio jack wire that I have cut off to do some experimental work? I have searched the internet and a lot of answers contradict each other.
jessica smith's user avatar
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1 answer
173 views

Understanding which P FET to use for reverse polarity protection

I use a Schottky diode as reverse polarity protection on earlier versions but have decided to change to something more appropriate and energy efficient. The voltage input on the left is a 12-14.8 V ...
robbrown92's user avatar
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2 answers
169 views

How can I determine polarity requirements for a device that is missing its power supply?

I have a MASSFIDELITY relay, wireless Bluetooth receiver for which the power supply is missing. I found a manual for the device that states it requires DC 5V 1A power, but says nothing about polarity. ...
Dustpan's user avatar
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2 votes
3 answers
78 views

Can polarity protection circuit be useful for also data transmission?

For example, CANBUS has two transmission lines CAN_HIGH and CAN_LOW. Polarity matters. Would the performance be affected if a polarity protection circuit with couple of diodes would be implemented? ...
alfonso's user avatar
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2 votes
2 answers
550 views

Ethernet devices polarity reversal support

Does all Ethernet PHY devices support polarity reversal even if its not mentioned in the datasheet? [I mean polarity reversal by swapping TX+ with TX- (Like connecting TX+ to RX- or TX- to RX+). Is ...
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-1 votes
2 answers
164 views

Does time constant or rise time concept apply in transformers as well? [closed]

I am new to electrical engineering. I have made a transformer where I kept one primary and two secondaries, there's an air gap between the primary leg and secondaries on toroidal core, you can watch ...
Yogie's user avatar
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3 votes
2 answers
993 views

I do not understand this polarity symbol with 3 circles: positive, round, negative, and no lines

I am trying to figure out what is the right polarity of a power adapter for a small practice amplifier. I know it is 9 VDC and I figured out the size of the plug and I know the wattage needed. I do ...
Freddy Montilla's user avatar
1 vote
2 answers
203 views

Is this the correct way to drive a double coil latching relay?

I have found a double coil latching relay which has the following diagram in the datasheet (http://www.fanhar.com/en/uploads/files/FH44L.pdf) : I am quite confused by the instruction "The common ...
photon-delight's user avatar
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0 answers
81 views

Determining Polarity Of Unmarked AC Adapter With Voltmeter

I need to replace an adapter that no longer works (for a fibre optic Christmas tree). I do not see any indications for polarity on the adapter (or anywhere else) and I do not have the manual. I read ...
Ken Boone's user avatar
0 votes
1 answer
152 views

Inductor polarity

By looking on the picture of the inductor PE-0402CL470JTT and the datasheet, we can notice a black pole and a white pole for the inductor. Is there any difference between poles? The datasheet doesn't ...
Softcity Seven's user avatar
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2 answers
98 views

Inductor voltage polarity

I am trying to understand the current direction during non-steady states of inductor. The circuit I am testing is very simple : ...
nikhilelite 's user avatar
2 votes
4 answers
1k views

Difference between phase and polarity?

Long story short, I did a bit of a career change, I'm now doing electrical engineering with an architecture firm instead of embedded systems. So I've jumped from the simple world of DC to the land of ...
audiFanatic's user avatar
0 votes
3 answers
319 views

Unusual Polarity Symbols on Universal Adaptor [closed]

The polarity symbols on my universal adapter look a bit different to ones I have seen. Which setting should I use to power the device shown please, top or bottom position for the switch on the adapter?...
Robin Andrews's user avatar
0 votes
2 answers
758 views

How to determine the voltage output polarity of a power supply

I have a high voltage power supply that can go up to 35000 volt. How do I test to see if the unit is outputting positive polarity voltage or negative polarity voltage ? What is the difference ...
Lynn1000's user avatar
1 vote
3 answers
160 views

Show polarity of magnetic pulse using two LEDs

I have made this simple circuit: In response to a rapidly changing magnetic field (pulse), the LED blinks. An example of the pulse is shown below: Now I would like to have a circuit with 2 LEDs so ...
Rasmus Friis Kjeldsen's user avatar
0 votes
1 answer
890 views

Is there a way to determine polarity of a DC device that has missing power adapter?

Let's say someone has bench power supply and a multimeter, then is it possible in safe manner without damaging device to use these tools to determine devices polarity? Update#1: In this specific case ...
user2138912's user avatar
3 votes
1 answer
145 views

Determining polarity of high voltage spark generator

I have a piezo ignition spark generator (Gasmate GMPIK-1) and I want to know the direction the current flows. I can't exactly hook it up to my multimeter because the spark only lasts for a fraction ...
Electron-Capture's user avatar
0 votes
2 answers
108 views

Changing the polarity of the transformer on DUT cause voltage offset on DC measurement with insulating amplifier

DUT (device under test) is powered by 230 VAC and for safety we use additional external 230 VAC - 230 VAC transformer (DUT also has its own transformer for buck converting). We are measuring DC ...
mrkefca's user avatar
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1 vote
2 answers
824 views

Ceramic capacitors soldering "placement/vertical" polarity

I was wondering, since multilayer ceramic caps have layers like this: Image source Aren't they supposed to (for better performance) be soldered on the PCB as the above picture shows aka parallel to ...
Christianidis Vasilis's user avatar
4 votes
3 answers
453 views

Polarity of TVS diode is unclear

I have a question regarding the DESD1LIN2WSQ TVS diode by Diodes Inc. which I want to use to protect some 24V IOs of a microcontroller board. Until now, the TVS diodes I worked with always had the ...
Sim Son's user avatar
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1 vote
1 answer
617 views

What does it mean to say that it has "opposite polarity"? Furthermore, what is meant by "isolation of the input and output ground references"?

I am currently reading the textbook Fundamentals of Power Electronics, third edition, by Robert W. Maksimovic and Dragan Erickson. In the introduction, the authors say the following: In a dc–dc ...
The Pointer's user avatar
  • 1,261
-1 votes
1 answer
442 views

Li ion battery polarity [closed]

For a Li ion battery showing 0 volts, should the negative connector from the charger go to the pin with 444,000 ohms or 362,000 ohms relative to common lead from a multimeter that was in contact with ...
QWERTY's user avatar
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1 vote
1 answer
176 views

How can I determine the polarity of an unmarked dc input?

I have a portable television with only a 12 volt input. The power lead is missing, which is not really a problem as long as I can identify either positive or negative. The socket is approximately 10mm ...
Muggs's user avatar
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2 votes
1 answer
240 views

Putting AC across polarised capacitors in headphone amp?

This circuit is from Fig. 20.3 in Douglas Self, Small Signal Audio Design, Third Edition, Routlege, 2020. This is a headphone amplifier, and as such, both input and output signals are alternating ...
Stephan Neuhaus's user avatar
0 votes
3 answers
123 views

AC circuit working principle

When a power source is AC (alternating current) one is a phase and the other is neutral. Does phase and neutral lines change their polarity over time or only phase line voltage and current up and down ...
belete getachew's user avatar
0 votes
3 answers
335 views

Does a signal that doesn't change polarity charge a capacitor?

I'm wondering if a digital signal that does not change polarity charges a capacitor. If the signal has a frequency of 1 MHz, does that charge the capacitor faster? And if so, is it possible to ...
Joggem's user avatar
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0 votes
1 answer
159 views

Polarity of inductor in GNSS antenna design

I was assembling a PCB today which had a circuit to connect the main module to an active GNSS antenna. I noticed that the inductor, a 47nH datasheet, had polarity markings on it, but I was unsure the ...
Feynman137's user avatar
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10 votes
5 answers
6k views

Why is this 3-way speaker wired this way?

I found a service manual of a pair of 3-way speakers that were part of a mini integrated stereo system. These are Sony SS-H77 speakers, which have served me very well back in the day. Looking at the ...
ysap's user avatar
  • 345
1 vote
2 answers
2k views

Peltier damage and efficiency when continuously reversing polarity

I am thinking about using peltier for both heating and cooling to maintain desired temperature profile in small area (2ft square at max) Can continuously changing polarity damage peltier module and ...
asim's user avatar
  • 590
0 votes
1 answer
206 views

Tantalum capacitor reverse polarity

I have a datasheet for a part (TPS6735IDR) that shows application circuit examples where polarised capacitors are connected the wrong way around (positive terminal to ground). I thought this would ...
jerrybenny18's user avatar

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