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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181 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 ...
1 vote
54 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 ...
45 views

Non-polarised capacitor (polarity when installed)

I was watching a youtube video in which it was explained that even non-polarised capacitors (mylar, polyester etc.) have to be installed with the "external plate" of the capacitor connected ...
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52 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 ...
59 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 ...
60 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 : ...
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447 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 ...
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72 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?...
132 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 ...
1 vote
107 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 ...
110 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 ...
52 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 ...
48 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 ...
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141 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 ...
265 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 ...
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1 vote
154 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 ...
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136 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 ...
88 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 ...
66 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 ...
98 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 ...
115 views

How to see reference antenna polarization in CST simulatiom

In Anechoic chamber we Test an antenna using another antenna. our test antenna result is based on the polarization of the reference antenna. in the simulated patch antenna bellow I can see the ...
158 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 ...
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50 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 ...
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3k 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 ...
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58 views

Why the border of 2 dielectrics can takes average energy density of electric field?

The ideal parallel plate capacitor exists and the upper space has been filled with the dielectric and same as the lower space. Each plate has been given $\pm Q$  \sigma :=\text{ surface ...
1 vote
265 views

Peltier reverse 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 ...
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114 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 ...
1 vote
83 views

Left and right circularly polarized antennas - which one to choose for reception-emission?

I've read that the spiral antenna is circularly polarized, either right or left circularly polarized, depending upon the construction. I want one antenna be the emitter, and the second one be the ...
• 1,706
73 views

DPDT Polarity Switch

I am trying to connect a USB relay to actuator, so when I press button 1 , motor goes up, when i press button 2, polarity is switched and motor goes down. I am trying to achieve this with a DPDT relay....
66 views

Can C3 in the schematic be polarized?

Here's the data sheet if it helps. https://www.cui.com/product/resource/pdqe15-d.pdf The DC\DC converter is an isolator unit so the left part of the circuit doesn't us a traditional GND, which leads ...
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86 views

10000 km Radio Polarization

If someone were to transmit short wave "Skywave" from the equator in the UTC+0 timezone (Greenwich Time) with vertical polarization, and the receiver is at the equator ~10000km away in the ...
66 views

Polarity Question for Powered Home Subwoofer

I picked up a powered home subwoofer at a garage sale. It did not have its power adaptor. All it shows is 12V DC (by the symbol) 2.5A. But it does not show the polarity anywhere on the subwoofer. ...
6k views

Is this an AC or DC signal?

My teacher says that this signal is DC, but if the polarity varies from 0V to -8V , shouldn't it be AC? He says that DC + AC = DC
145 views

Direction of N-channel mosfet when replacing the diode in the buck convertor

In a buck-converter with a diode, in the first and second phases (on and of states) current is supposed to flow like the following circuits: I am looking for a way to replace the diode with a MOSFET ...
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142 views

Inductor Polarity Reversal - Flyback Voltage

I have a question about how to intuitively think about the polarity reversal (flyback voltage) that occurs in an inductor when removed from a supply. Here is my understanding: When the switch is ...
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Amp issue with buckboost plus usbc decoy setup

First I would like to say that I am a software developer with limited skills in electronics. I am trying to build a setup to charge my electric longboard batteries from an usbc power delivery input. I ...
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59 views

reversing DC polarity after each use

My touch faucet died. I can use a z44n mosfet to activate the solenoid with the 6V battery pack but I need to have the polarity switched each use to drive the solenoid in the opposite direction with ...
144 views

Polarity issue in JFET transistor

I'm wondering what determines the polarity conditions in a JFET - is it that this transistor can only operate when the p-n junction is in reverse biased polarization? If so, what about the states of ...
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142 views

Identify polarity of 1970's-era dipped tantalum capacitor

Having found the shorted component, now I need to replace it. I'm familiar with dipped tantalum capacitors with painted stripes along one side but these have a dot or stripe up the middle and my Web ...
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48 views

Simple low-power remote switch

I volunteer with a charity making aids for people with a disability. My current project is a key-fob gate latch for a client who can't reach a latch from the wheelchair. I have only a bit of hobby ...
157 views

How is it possible to replace a relay with transistors?

As we all know: A relay's COM and NO pins have no polarity, they will work fine when polarity is reversed. A transistor's Collector and Emitter pins have polarity and this polarity must be respected. ...
1 vote
150 views

How to detect USB data polarity?

Assuming we have a USB (1.x or 2.0) device and know what pins are for +5 and GND, is there a general way to detect which of the ...
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50 views

Replace LED chip with reversed polarity pin-out

I want to upgrade the LED chips of a projector. Red: PT-120-R-C11 --> PT‐120‐RAX‐L15 Green: PT-120-G-C11 --> PT‐120‐G‐L11 Blue: PT-120-B-C11 --> PT‐120‐B‐L11 But the red LED chip (PT‐120‐...
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2k views

My strands of LED Christmas lights are not polarized, and I don't understand how that works

I have several long strings of LED Christmas lights. Each bulb socket is obviously polarized, with one contact being much lower than the other and the LED bulbs only fit in one way. But the plug at ...
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107 views

Difference between $\epsilon$ and $\epsilon_0$?

I have been given the following equation for the speed of light: \\$V = \Large {1 \over {\sqrt {\mathstrut \epsilon \cdot \mu}}} = {1 \over \sqrt{\mathstrut \epsilon_0 \cdot \epsilon_r \cdot \mu_0 \...
1 vote
69 views

Buck-Boost polarity

One of the disadvantages of a Buck-boost converter is the minus sign at the output (Transfer function of Vo/Vin = -D/(1-D) ) My question - Why can't we just place the load rotated? Wouldn't it solve ...
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1 vote
314 views

Using h-bridge with LED fairy lights

I have a string of LED fairy lights (5v) that when I connect to power, only half of them light up. If I reverse the polarity, the other half light up. It’s my understanding that I need a h-bridge to ...
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1 vote
807 views

Converting LED fairy lights from battery to power

I have a set of LED lights that I like that only have a battery pack option. To make it work, I cut the battery pack off and wired it to a 5V power supply. Only half the lights turn on at a time. If I ...
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