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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758 views

DMM Auto-Polarity / Polarity detection

I have understood how auto-ranging is typically achieved on a digital multimeter, but I'm having trouble finding an example of how (DC) polarity is handled. How does the meter know if a voltage is ...
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2k views

simple h-bridge polarity reversal

I am trying to reverse the polarity on a rather beefy motor (5 amp, 60v) in the most simple way possible. I need to build an h-bridge just to reverse the current, I am controlling speed elsewhere. ...
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177 views

Proper Flyback Current Protection Circuit for Variable Voltage Solenoid Driver

I am using a darlington buffered op-amp to drive a solenoid motor at variable voltages (for variable speeds of actuation). Here is my circuit as it is now: I am wondering which of the two flyback ...
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250 views

Protecting against reverse polarity

I'm building a JTAG programmer for the old Motorola 56k devices and I want to add some circuit protection before having some boards built. I'm more of a firmware/digital guy, but here's what I came up ...
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721 views

Slot assignment in JST SM connectors

I am using JST SM connectors for connecting two sets of wire. There are two slots in 2-pin connector. I wish to know, what is general convention for assigning the polarity to these slots? Is it slot 1-...
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277 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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792 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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407 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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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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58 views

EM wave polarization check

I am trying to recall the quick way to check the EM polarization theoretically, I mean if I have a wave described as (ssume capital letters are vectorial fields) \begin{equation} \ E = E_o *exp(j* \...
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7k views

Coil Winding Sense of Inductor/Transformers and Output Polarity

Given a solenoidal coil, if it is wound in one sense (say clockwise), would the output from it, in terms of polarity, be equivalent to another coil, wound in the opposite sense (counter-clockwise), ...
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21k views

limit switches to control motor direction

I am trying to use two limit switches and two DPDT relays to control the direction of the motor. When the power is applied the motor should rotate one direction (direction for this question isn't ...
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1answer
2k views

Changing the polarity of electromagnet using H-Bridge

I have made an electromagnet using copper coil of 1.0 mm diameter, iron core of 2 cm dia & 8 cm length for my project. Supplied voltage is 12 VDC and current it consumes is 9.0 Amp. It has 1.5 Ohm ...
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3k views

How do the hybrid-pi models between N-channel and P-channel JFETs differ?

This is the hybrid-pi model of an n-channel JFET. An answer on here claimed that the only difference between p-channel and n-channel JFETs is that voltages are reversed. How would this apply to the ...
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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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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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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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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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533 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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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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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 ...
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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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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 ...
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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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7k views

Motor polarity reversing circuit using just SPDT switches

I have a 6v DC motor that controls a physical system similar to a window blind, using one SPDT toggle switch and two SPDT microswitches for control. I have seen similar setups with hoists, however I ...
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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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3k views

How to fix servo motor broken by wrong polarity [closed]

I accidentally plugged in my servo with the wrong polarity (with the order of wires being signal, ground and power). It immediately started releasing the 'magic smoke', but I managed to unplug it ...
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3answers
222 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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195 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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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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74 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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239 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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2k 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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92 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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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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129 views

Why are the polarized caps backwards?

I'm having trouble with this circuit, It is showing capacitors to ground in two different ways. Would anyone be able to help? And could I used polarized instead of non polarized?
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730 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
2k views

How to figure out polarity of a polarized capacitor in a circuit

I've found myself a number of time trying to build a circuit from a schematics that does not provide any polarity indication for caps (probably because the designer used non-polarized caps in the ...
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1answer
1k views

Capacitive transformerless power supply, AC polarity problem

I have implemented a "Capacitive transformerless power supply" to control a microcontroller-based circuit that contains capacitive touch sensors, and I had an "AC polarity problem" Surprisingly, the ...
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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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271 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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1answer
131 views

Motherboard's 4 pin DC input polarity

I have a motherboard, that requires a DC input. The manual has this: I'm trying to find a power brick, but all bricks I can find usually have +12V/-12V on pins or shell and no ground. Can I use them?...
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287 views

What types of signals can a dynamic microphone generate?

And what design generates what type of signal property? For example there are dynamic mics with or without output transformers. Do they differ in the type of signal outputted? Do most dynamics ...
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1answer
481 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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2answers
442 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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1answer
72 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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299 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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4k 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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3answers
632 views

How to change the polarity of 0~5 volts get -5~+5 volts?

I am doing a project using NI DAQ USB 6008 to control an speaker. The DAQ analogic ouput range is 0 to 5 volts and the output current drive is 5 mA. But to control the speaker I need a different range....
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326 views

Does biphasic wave mean current is bidirectional?

Does biphasic wave mean current is going bidirectional in a circuit?