# 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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### 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 ...
47 views

### 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 ...
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 ...
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. ...
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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### 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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### 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 ...
151 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 ...
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 ...
2k views

### Ubiquiti/UniFi PCB component identification and polarity question

I stupidly dropped a brand new Ubiquiti UniFi AP-LR wireless access point on the floor. The impact broke off a component (shown in the picture) from the PCB which is preventing the AP from working ...
433 views

### Op-amp: Floating input (Multisim)

I found this circuit from Encyclopedia of Electronic Circuits Volumes 1 by RUDOLF F. GRAF I used Multisim to simulate. When switches S1 and S2 are open (U1A@3 and U1B@6 are floating) and I measured ...
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### 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....
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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### 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 ...
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 ...
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 ...
382 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 ...
196 views

### Undervoltage/capacitor problems with Raspberry Pi

My question is about the correct way to add a capacitor to a circuit with a Raspberry Pi driving a servo. I have seen undervoltage events in the logs of my app when the servo runs so I added a 470uF/...
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### Transformer windings - Polarity - FEMM

I am designing a transformer in FEMM and I was wondering about the polarity of the windings. The following figures illustrate two cases. When I run the simulation, the magnetic field in the first one ...
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### How do I know the polarity of the resultant voltage of these two series-connected alternating voltage sources?

I was studying simple vector addition on All About Circuits, and the polarity assigned to the resultant voltage (see picture below) confused me. Link: https://www.allaboutcircuits.com/textbook/...
83 views

### How to connect a generator and LED device of different polarities?

I have a device that generates light impulses when connected to a LED device. The intensity of the light is regulated by a potentiometer, within the generator. There are 2 independent channels. The ...
84 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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### 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-...