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").
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Is this a functional and reliable Reverse polarity protection?
Guys, I am trying here to design a UPS controlling board, I designed this circuit and it was to some extent functional and it draws approximately 16mA - 20mA (I don't want to use the traditional one ...
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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 ...
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High voltage polarity inverter circuit
I'm building a cloud chamber which needs to use an high voltage source. I'm using an electric fly swatter circuit which can generate about 4kV. The fact is that I want to use a button to switch the ...
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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 ...
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Selection of MOSFET
The datasheet for the LM74700-Q1 states that "The maximum V(gs) that the IC can supply is 13V, so a MOSFET with 15V minimum V(gs) should be selected."
I don't understand for the MOSFET to be ...
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Having trouble understanding sink current values for an LM74700-Q1 ideal diode controller
This is my first time referring/understanding a datasheet.
As I understand it from a quick search, a sink current is the current (negative) which flows into a port, while source current is the ...
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(−40)–(40)V P-channel MOSFET based reverse polarity protection
I'm building a P-MOS based reverse polarity protection circuit.
The input requirements are as follows.
It needs to carry 8–40 V input voltage to the output and it needs reverse polarity protection up ...
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How to add Reverse Polarity Protection on 2-cell battery charger IC?
I'm using the MP2672A (datasheet) 2-cell balanced charger IC for charging 2 li-on batteries. Normal PFET reverse polarity protection (RPP) doesn't work here as the IC has a balance function which ...
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Protecting Polarized capacitor from reverse voltage
I have a circuit with a P-channel MOSFET based reverse voltage protection. Will the polarized capacitor be "safe" if a reverse voltage is applied to the below circuit?
I've mocked it up in ...
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Reverse Polarity Protection for GPIO header powered Raspberry Pi 4: Diode with 1, 2 or 5 A?
For my project I power a Raspberry Pi 4 over the GPIO header. I use a breadboard which looks like that:
In order to protect the Raspberry from reverse polarity I thought about a simple solution: I ...
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Best overvoltage and reverse polarity protection
I would like to add overvoltage and reverse polarity protection to my circuit.
Searching on the internet, I saw that the solution that seems to be the most popular is this:
I have seen there is a lot ...
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Protecting a battery charger from reverse polarity
I am building a battery charger for AGM (lead-acid) batteries that will output max. 5 amps to charge the battery, through a pair of clips. This makes it a possibility that the battery could ...
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Reverse polarity protection for 320 VDC, 20 A
I would like to add reverse polarity protection to my robot. Supply is 320 VDC, 20 A max. The load is mainly inductive (DC brushless motors, some DC/DC converters).
A simple solution would be using a ...
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Reverse polarity protection with two-cell series Li-ion
I plan on using a P-channel MOSFET for reverse polarity protection. The MOSFET I chose is the SISS27DN-T1-GE3 - it has a 30 V VDS, ~5.5 mΩ RDS, and +/-20 V VGS.
Since this MOSFET has a higher VDS and ...
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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 ...
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Circuit protection with multiple USB ports
I'm making a breakout board for an ESP32-S2-MINI-2 module.
This module has USB OTG capabilities and a UART interface, which is usually exposed with a USB port via a USB-UART converter.
I would like to ...
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Protecting an op-amp's 0-10 V, 5 mA outputs against 24 VAC being connected to them
I have a circuit with four 0-10 V, 5 mA output channels on a PCB designed to work for ventilation, where the output valves are powered by 24 VAC. It is to resolve a problem we have at work with 350 ...
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What is the difference between active reverse polarity and reverse polarity protection in a circuit?
What is the difference between active reverse polarity and reverse polarity protection in an electronics circuit? In battery operated we are giving the reverse polarity protection.
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What manner of reverse voltage protection circuit should I add to this schematic?
This is a continuation from my previous post where I asked for feedback about my designs. There was a lot to say about them. In trying to follow all of the advice I was given, and applying all the ...
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Reverse polarity protection circuit consumption
I found this reverse polarity circuit that uses a matched PNP pair and a MOSFET: https://projects-raspberry.com/raspberry-pi-b-power-protection-circuit/
I tested this circuit and with no load i get ...
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Is it possible to modify a commutator to make a DC motor oscillate at 180° without a full 360° turn?
I can understand how a DC motor works, and keeps rotating in the same direction with the split design of the commutator. The following (simplified) picture nicely explains it:
From here.
I know we ...
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What do I need to connect an R-SMA male to a standard coaxial male? [closed]
I have a router that has the following type of pigtail connector soldered to the board which I believe is an R-SMA male coaxial cable.
I'd like to connect it to a standard male coaxial cable that's ...
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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 ...
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Understanding which P FET to use for reverse polarity protection
I use a Schottky diode as reverse polarity protection on earlier versions but have decided to change to something more appropriate and energy efficient.
The voltage input on the left is a 12-14.8 V ...
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What is the function of a capacitor between source and gate in this reverse polarity protection circuit?
I want to incorporate a simple reverse polarity protection to my design. I stumbled across this circuit in the Raspberry Pi Compute Module 4 IO Board schematic:
I understand how the Q1 + D4 + R26 ...
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MOSFET for reverse current protection?
I have a package-integrated charging module connected to my 2-cell battery. When the charger is inactive (disconnected from input voltage), the charger eats power from my battery. I thus want to ...
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Reverse spike protection via MOSFET
M3 has |Vds| > 300V |Vgs| = 10V
Protecting the load from V1 = -300V 100ms spike:
Does this diagram, with carefully picked components, look like it will do the job ? Hw do I select R1, D2 and D3 ?
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Speaker protection circuit with polarized capacitor seeing reverse voltage. Why? How?
I am looking at this speaker protection circuit found in a vintage Technics receiver.
The signal from the speakers comes from the wire highlighted in green, coming from the output of a class AB power ...
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Looking for advice to prevent reverse current flow
I have only rudimentary knowledge of circuit design and need some advice.
I have a printed circuit board used in a device for automotive applications. I would like to include the means to prevent ...
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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?
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What is the use of a P-channel FET on a power line?
I was going through a schematic of one controller. I found this circuit for the VIN pin:
What is the DMG2305UX (Q1) P-channel MOSFET used for?
I have read that MOSFETs are used for reverse polarity ...
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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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Safety of a polarized DC breaker between the battery and the inverter
DC breakers use a magnet to blow the arc into the quenching channel. If the current is flowing in the wrong directly, the arc is pulled into the guts of the breaker and can cause the arc to be ...
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High side reverse voltage and overvoltage protection circuit
Can someone provide an explanation why I still have a 50Vp negative waveform after the rectifier (waveform on Vch2) and after the overvoltage (output voltage) we have the same positive cycle.
It's ...
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Charging supercapacitors with reversed polarity
I bought six supercapacitors and connected them in series to get a total voltage of 16.2 VDC.
The product's Mouser No is: 723-BCAP0450P270S18, Mfr. No is: BCAP0450 P270 S18, the datasheet can be found ...
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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:
...
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Problem design a reverse polarity protection circuit
I´m trying to develop a circuit that is able to control a starter motor with mosfets and also send a signal to control an external relay. I was able to control the starter motor through the help of a ...
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Reverse polarity protection without Zener diode
I find the following reverse polarity protection circuit everywhere online.
Reverse polarity protection using PMOS and Zener diode:
Can you replace the Zener and resistor with a voltage divider as in ...
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Capacitor with reverse polarity
In a "Snap Circuits" project ("Leaky Capacitor"), the instructions have me put a 470 uF polarized capacitor in backwards with the negative side towards the batteries. This is to ...
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Adding nFET-driven reverse polarity protection to a switching regulator input
I'd like to protect my board mounted switching regulator's input from reverse polarity events without having to modify the existing run of boards we had created and populated. The primary regulator ...
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Does this diode make any sense in this circuit?
Here is the entry stage of power circuit for an Arduino clone. Input voltage 7-12V DC, MP2307 regulates it down to 5V. Diode D1 is presumably there to protect against reversed polarity, but it will ...
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How to protect this circuit from shorting out / reverse polarity?
I'm building a device that uses multiple TRS jacks for power and communication. (I know that audio jack is not the best choice for power but it's important for overall design and I really want to make ...
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Breakdown voltage in diode and Zener diode, what are the practical differences?
Until now, I've only studied with diodes asuming they are ideal and I could tell the difference between normal diodes and Zener diodes. Now, I started to study non-ideal diodes and I see that this non-...
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PMOS reverse supply
I'm a little confused, can someone explain to me why this circuit conducts?
I thought that the body diode of the PMOS was in reverse polarity and the source node of PMOS should be at 0V, but ...
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Power consumption for reverse polarity protection using p-channel MOSFET
I'm looking for a way to implement reverse polarity protection for a circuit that runs from a CR2032 battery (The operating voltage of the circuit is from 1.8 V to 3.2 V).
I'm considering using the ...
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Polarity reversing by using laser sensor for signal
To edit this question I should add that I won't be using a switch I'm using a laser sensor so when a object passes in front of it the laser sensor will send the signal voltage.
I'll be using a laser ...
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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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Power MUX Circuit with 5V & 3.3V Regulation + Reverse Polarity Using LM358 - Questions & Concerns
I'm working on a circuit that can be powered via USB or via header pins.
The goals are:
The MUX will determine, and prioritize, the higher voltage supply.
The MUX will provide reverse polarity and ...
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MOSFET as reverse polarity protection and power switch too
We have a system where there is main power supply as well as a single cell Li-Ion battery (4.1 V to 3.3 V range we'll use) as a backup battery. Its a low cost and PCB area constrained product. The ...
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MOSFET voltage drop seems way too high
As discussed here, I'm trying to use a MOSFET for reverse polarity protection.
I got an IRFB7440PbF, which has a low Rds(On) (2mOhm,) suitable Vgs (I'm using a 5V power supply,) and what I thought ...
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