A device, components, or safety measure designed to protect circuits from overvoltage, overcurrent, a combination of these; or the theory of same.
Questions tagged [circuit-protection]
653 questions
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AC: Why differentiate between Ground and Neutral?
Current flows through a conductor connecting points at different potentials.
Leaving aside multi-phase details, common/conventional AC systems use a 3-wire setup:
Wire-1: a line/live/hot/phase wire presenting a point that oscillates between 2…

BVN
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Due to overcurrent, shouldn't I be extremely cautious when setting an I/O pin as Output?
The question can be applied to any microcontroller with I/O capabilities, but I’m currently working with the popular ATmega328p. Consider the following circuit: A simple SPST Normally Open switch with a 10k pull-up resistor and a ceramic capacitor…

Julian Zatloukal
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Reverse polarity protection circuits all seem wrong
I've been looking into reverse polarity protection and come across a lot of resources that recommend using a P-channel MOSFET with a Zener diode.
Every single one of these circuits shows the MOSFET reversed - as if current was flowing from…

InBedded16
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Why (not) put a resistor on FET gate?
While thinking of ways to protect a MOSFET one idea was to put an extremely high resistance in front of the gate: The idea being that current is never supposed to flow through the gate, so if some transient threatened the gate, the resistance would…

feetwet
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Why is there sand or salt in this electrical circuit?
Can anyone tell me what this is and why this sand-like thing is used in an electrical circuit? I have never seen this kind of thing.
About the components: they are in an "electricity saving spike buster". When I saw it at my parents house I of…

wtknow
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Is it worth it or safe to design your own power supply?
I am currently building some kind of game console based on a Raspberry Pi, with some features (one discussed here), right now I am using for this project a Meanwell power supply.
However, I was thinking to design soon or later a PCB instead of…

Varech
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How can I use two TP4056 with two li-ion batteries, but single load?
I have two TP4056 modules (with protection circuit), which I am using to charge two batteries respectively, off a single power line. The modules are the ones that have charge output (B+/B-), and another regular output.
I'd like to be able to use…

Mr.M
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How does this overvoltage protection work?
I was looking around for low cost and effective overvoltage protection, and I found this from this page:
With this part list:
RXE025 - 250 mA PTC resettable fuse
Zener diode – 5V6, 1 watt
Resistor – 1K ohm, 1 watt
Transistor – BD139 (NPN medium…

VirtApp
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What is the recommended way to protect a circuit from non-transient overvoltage?
I'm designing a 12V battery-operated portable lighting controller, and frequently am asked about improving the run time. The simplest way is to add a second battery in parallel, but I often worry that users will get it wrong, hook up the batteries…

JYelton
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Protecting a laptop from USB connected devices
In the past couple of months I've managed to destroy 2 perfectly good laptops through programming development electronics through USB. I've been wondering what could be done to prevent this. A couple of ideas I've had (not sure how practical):
USB…

andowt
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For mains attached circuits: what do I need to protect against and how do I do it?
I don't have a lot of experience with mains voltage and designing protection circuits for them. I'm not sure:
A) What do I need to protect against? I know I don't need to worry about 10kV voltage transients on the mains line, but what about 300V…

Andrew Spott
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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 aren't starter circuits protected?
In most cars and trucks, a thick cable connects the battery directly to the starter (solenoid). Why don't these circuits have have any kind of overcurrent protection?
It is an accepted practice throughout the motor vehicle industry. Here are two…

csanders
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Will this reversible USB-A circuit work safely?
I'm working on a PCB USB stick with a reversible USB-A connector. This device should work reversibly with any normal USB host.
I know that it works fine with just the topside, but I realized it could be reversible with the traces added on the…

Conor Patrick
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TP4056 module parallel output
this is my first time asked on stack exchange, please bear bare with me.
Anyway, I created portable monitor using multiple TP4056 as battery charger & protection circuit. But I'm not sure it's safe or not.
this is the wiring diagram :
why I wired…

vein sekundes
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