Questions tagged [reverse-polarity]

For questions about the operation and/or protection of polarized electronic components when biased in reverse. Consider also using the "protection" tag and/or tag(s) for the polarized components in question (e.g. "diodes").

For questions about the operation and/or protection of polarized electronic components when biased in reverse. Reverse polarity protection is required for many polarized components (e.g., batteries, capacitors, etc.), though in some cases components are capable of operation when biased in reverse (e.g. diodes) or are possibly even intended to operate in reverse (e.g. Zener diodes). Consider also using and/or tag(s) for the polarized components in question (e.g. ).

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How does USB Type C handle reverse polarity / signal duplication

The new USB Type C connector doesn't have a physical reverse polarity protection any more. You can plug it in any way you want on both ends, there is also no A and B end any more, it's all the same. So how does this new USB type handle that the…
timonsku
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Do serially connected diodes share equal reverse voltage?

If I place three cheap 200 V rated diodes across a 500 V supply instead of one expensive diode, is the system guarantied to work correctly? My worry is the situation at which two of the diodes share 150 V and the remaining 350 V appears on the other…
hkBattousai
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Does an electrolytic capacitor degrade each time it receives reverse voltage?

I know that I mustn't connect an electrolytic capacitor reversely. It will explode if I apply the reverse voltage long enough. But, what happens if the reverse voltage is applied for a short time? For example, a fault occurs in the circuit and the…
hkBattousai
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Why is there a polarized capacitor symbol in an AC circuit?

I am confused. My question is very basic, someone please enlighten me. If polarized capacitors should not be used in reverse polarity then why does every textbook (like the one I am using, Grob's Basic Electronics) show polarized capacitor symbols…
Asim
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Please suggest any improvements for this reverse polarity protection circuit

I'm using this circuit for reverse polarity protection. The load draws 20A (11 DC motors) continuously for 2 hours after which the battery gets replaced. Even with a heat sink, the MOSFET gets extremely hot. Whenever there is a battery swap, I…
WhiteShark
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Is reverse polarity protection this simple?

I am working on a PCB design and need help understanding reverse polarity protection. The board will be powered with a 12V 5.4A power supply via barrel jack. I am planning on using this chip because according to my (admittedly new) understanding of…
alexoiunt1
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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 wiring diagram (below), there is something very…
ysap
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Which reverse polarity protection is better and why?

You can find two such circuits using a diode that protects against reverse polarity, i.e. against wrong power connection. I wonder what is the point of using the D2 diode, since the current flowing through it will damage it - at least that's what…
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Designing an effective power supply for embedded products

I'm currently designing several embedded microcontroller products to be powered from a wall outlet. I plan to use wall-wart power supplies to give an input of approximately 5-9V DC but I want the input of my device to work at up to 30V just for the…
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What problem is solved by using a PMOS for reverse polarity protection instead of an NMOS?

Many resources suggest the use of a PMOS for reverse polarity protection instead of a diode, as it decreases losses. However, the characterstics of an NMOS are better than a PMOS, so why is using it for reverse polarity not often mentioned? Here's…
Anas Malas
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Maximum reverse voltage applied to a resistor-LED configuration

Consider the simple circuit below: simulate this circuit – Schematic created using CircuitLab LED datasheet: link Will the applying of a reversed 36 V to this circuit damage the LED? Knowing that the maximum current that could flow into the LED is…
fhlb
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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 in its EMF to keep the voltage at its original…
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Does the HT73xx LDO regulator series have reverse polarity protection?

I can't find in the specs if the HT73xx series has any kind of built-in protection against reverse input polarity. What happens if I feed it -10 V instead of +10 V?
Mathieu
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Selecting series resistor for a Zener diode

I am currently designing a device that will be powered by eight AA disposable batteries. For reverse polarity protection I am looking to use a P-channel MOSFET in the following configuration: simulate this circuit – Schematic created using…
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How to protect input against both ESD and reverse polarity?

I need to protect an external input on a device against both reverse polarity and ESD (IEC61000-4-2 +-8kV). The normal input is +5V dc at 100-200mA; the reversed input could be -5V and that should be blocked (maybe with a few uA leakage). I tried…
Alex I
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