Questions tagged [circuit-protection]
A device, components, or safety measure designed to protect circuits from overvoltage, overcurrent, a combination of these; or the theory of same.
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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 ...
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Over voltage and reverse voltage protection of multiplexed ADC with voltage follower
I am designing a protection circuit for the ADC section of a design I am working on.
There will be 8 analog signals being read by a single pin of the MCU via an 8 channel multiplexer. The analog ...
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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 ...
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Reverse-polarity protection P-channel MOSFET
There are many ways one can build a reverse-polarity protection circuit. Using diodes, Shottky diodes, n-MOS in the return path and using a P-channel MOSFET on the positive side of the circuit. My ...
user233583
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AC constant-current source design
I want to provide a fairly constant current (say 10mA RMS, peak 20mA, of 60Hz AC, using a 120V supply) to a load of highly variable resistance. It doesn't have to be super-clean or precise, but ...
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Apparently open circuit resistor with 5 bands and white final band
I'm trying to measure this resistor using an analog multimeter which has resistor parameters from X1 to X10k, but whatever parameters I set to, the needle doesn't move.
The resistor unusually has a ...
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Protection Against High/Negative Voltage for Arduino
I am currently on a student project where I have to create a portable device that allows the output of sensors connected to it to be displayed on a 16x2 LCD screen using an Arduino Uno R3.
One of ...
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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 ...
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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 ...
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±12V protection for MIDI output
TLDR; how to make a MIDI output withstand shorting it to \$\pm12\$V?
I'm designing a MIDI output in a eurorack modular synth module on a TRS jack (this is a semi-standard non-standard way to save ...
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±12V protection for MIDI input
TLDR; how to make a MIDI input withstand shorting to \$\pm12V\$?
This is a counterpart to this question, I'm asking this as I was inspired by the great answer I got there.
I'm designing a MIDI input ...
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Will a RCBO 4P trip in case of neutral fault/failure/interrupt/float?
We have 3 phase power supply in my home which is used to power single phase 240V 50 hz appliances with common neutral. (Diagram in the link at the bottom)
The only protection we have as of now are ...
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How can I protect my MOSFET?
I'm using this depletion-mode MOSFET in a high-voltage power-management circuit. My 500V DC supply isn't high grade, and now that I've blown two of these MOSFETs (gate shorts to drain) I'm wondering ...
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What could be this component and what is its work? Is it a fuse or may be a protection resistor? [duplicate]
I opened before some laptop batteries. But this is the first time I see it. This is an IBM ThinkPad cell battery.
See picture below, the two pins to the left are connected, resistance between left-...
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current/voltage isolators in cars
When I attach something sensitive like a analog camera and LCD screen to a car battery along with a switched high amp load like a power door lock actuator, I get video problems when the load is ...
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How does diode clamp protection work?
I am not able to understand how diode clamp protection works.
Considering the diode clamp protection as shown in Figure 1: When the input voltage (Vin) becomes more than power supply voltage (Vss = ...
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MCU Input Protection
I am working on a simple protection circuit for an I/O pin on an MCU. The device will be 3v battery powered. The MCU's I/O pin has a voltage tolerance of (GND - .6V) to (Vdd + .6V).
Pull-to-ground ...
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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 ...
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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 – ...
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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 ...
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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 ...
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1-Wire DS2480B overvoltage and ESD protection
I'm designing a series of 1-Wire components for my SmartHome Bus and use the DS2480B as Busmaster. Because the cable I run around the house has 3 wires (24V, 1-Wire, GND), I'd like to protect the ...
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How to protect microcontroller board 1-wire from accidental +12V connection?
I'm working on modular LED strip driver with one "Master" board and up to 32 "Slave" boards. Each "Slave" board drives one LED strip.
All boards have 3 pin terminals:
+...
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Reverse Polarity Voltage Protection Using P-MOSFET
Could you please help me understand why in a reverse polarity circuit with P channel MOSFET Source of the MOSFET is connected to the LOAD and DRAIN to the power supply?
I understand the concept of a ...
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IC protection diodes confusion
This question is (loosely) related to my previous question here.
I wanted to check the ESD protection diodes of the LPC1114 MCU from NXP. So I measured all pins on a brand new LPC1114 MCU with a ...
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What is the metallic coating on these stranded copper wires?
The 5-colored wires's strands looks like aluminium, but it is basically copper wire at centre, with a thin conductive coating (my teacher shown it to me) of silvery-color, so that the copper doesn't ...
user107801
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How does a zener protect my microcontroller?
I'm connecting a 12V inductive limit switch for my 3d printer to a RAMPS controller (Arduino-based printer controller).
The RAMPS board operates at 5V, and connecting the 12V signal from the limit ...
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Safety of dual male / single female Y cords
On Amazon there are Y cords with two male plugs and a single, higher current female socket. These are advertised as providing a way to power equipment with higher current demands than a single outlet ...
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Is it possible to use a MOSFET for Li-ion reverse polarity protection when protecting a charger?
I've made a simple charger out of 4 TP4056 modules and 4 18650 sockets. These modules have overcharge, undercharge and overcurrent protection included, but I also want to know how simple it would be ...
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Li-Ion Protection IC Always in Overcurrent Detect Mode
I am seeing an issue with AP9211SA-AF-HAC7 Battery management system.
The battery protection circuit, designed as per the schematic attached (the same as the reference design in the data sheet(https:/...
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Designing Under/Over Voltage LiPo protection circuit
I am currently trying to design a protection circuit for a project of mine that uses a single cell 3.7v lithium ion battery. I found this image online which uses 2 TL431s:
However, I am really not ...
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Opinions on what I've come up with for a 12 V-to-5 V automotive circuit?
Is this a solid solution for an automotive 12 V-to-5 V circuit to power an ATtiny? I've been trying to come up with a solution for my needs that can handle the automotive environment that is so scary ...
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Does an overvoltage TVS for USB hot-plugging connect to shield ground?
I am designing a keyboard which will connect to the computer via usb-miniB to charge a LiPo battery. The datasheet for the charging IC I am using specifies overvoltage protection on the USB power ...
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overshoot and undershoot on 3 volt pulse
i am interfacing a system, this system output signal of 200ns digital pulse with repetition time of every 3ms. Ideal voltage of signal would be 0v to 3.3V but signal coming from system have high ...
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Dimensioning SCR crowbar circuit
I need to dimension an SCR crowbar circuit to reach a certain level of protection against overvoltage, without increasing much the complexity of the circuit of my control card. The need is to protect ...
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24V Circuit Protection - Fuse, TVS Diode, RC Snubber
I have pored over data sheets and read numerous articles on circuit protection. I understand conceptually, but I don’t trust my level of knowledge to implement it optimally. I want to be as specific ...
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How to protect a P-channel MOSFET when driving a motor?
I want to switch a 12 V DC automotive fuel pump in a bench test rig using a P-channel MOSFET, as follows:
simulate this circuit – Schematic created using CircuitLab
This is a simple on/off ...
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Should I use two fuses for 220V mains?
I'm designing a product that will be fed directly from 220V mains. The 220V goes into a PCB that has a high voltage section and a AC/DC converter module to generate low voltage to the microelectronics....
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What's the purpose of this RC filter?
The circuit is the following and i think this RC filter is used for anti debounce purposes but i'm not sure. Is it to prevent the optocoupler and the indicator LED from being "damaged" by the debounce ...
user106293
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Resistor placement for Zener diode for over voltage protection
I have searched in over voltage protection (like MOSFET.) I wanted to use a Zener diode in parallel so it won't dissipate power unless in over voltage protection, but its power is low so I read that I ...
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DW01A not allowing power in TP4056 circuit
Edit: Used wrong resistor at R_BAT1. The schematic was correct, the part I used was wrong.
I am using the following charging circuit. It is the standard circuit taken from the datasheets. But it is ...
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Understanding STEVAL-ILM001V1 DALI transceiver schematic + adding protections
I'm working on implementing a DALI bus interface circuit.
DALI has a few specifics that make this tricky: The device should draw at most 2mA when receiving, it transmits by shorting the bus (250mA is ...
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Type-C Non-Negotiated Power and 20V protection
I'm developing a 5V device and I use 5V for powering/charging the device. I googled the subject of course, and came to the conclusion that 5V device should have 20V protection in case there is some ...
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Blown fuse detection parallel battery bank
I have 384 Nissan Leaf battery modules that I wish to design a blown fuse monitoring system for.
Each module consists of 2 x LiIon cells in series with a separate fuse for each cell,
The modules are ...
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Will this NMOS MOSFET reverse-polarity protection circuit work?
Based on the helpful advice from the community, I realised the first schematic I made would not work as a protection for reverse polarity well due to a couple of flaws including the diode having to be ...
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Reverse current protection on power-switching MOS
It was suggested in "Select power supply voltage using MOSFETs" that a second MOSFET can be added in series to prevent reverse current flow.
My question is, can I just reverse Drain and Source on the ...
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DC1601B Demo board input line caught fire during use
I am using a DC1601B-C buck-boost converter in an automotive circuit to power some various electronics that I have added. It worked fine for a couple months, but under a less-than-normal load of 2.25A ...
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Protect DC circuit from AC
First and foremost, I would like to point out that I am a beginner in electronics.
I have designed a board that is meant to be connected to 240V AC. However, there is a relay on it that has a 12V DC ...
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Identifying Value of Burnt 5-Band Resistor with White Last Band
I've been having trouble identifying the value of this resistor (see picture below) as the color codes in position does not make sense. It looks like a 5 band coded resistor. The 3rd band seems to be ...
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Solar charger for Lipo battery
Im trying to build a little solar charger for a Li-po battery using
2 solar panels rated at 6V/120mA
a linear charger based on the TP4056 chip
The idea is to connect the two panels in paralel so ...
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