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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Need help in understanding the mosfet reverse polarity protection circuit

I am working on reverse polarity protection circuit. I found out that most of the people are using the circuit as is mentioned below. I have few concerns regarding the direction of MOSFET Why is it connected in reverse direction (because if you…
niks
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Reverse polarity protection using MOSFET - what is the voltage drop after it?

I am using this schematic for reverse polarity protection of an IC (bq78412). However the same IC has an ADC that senses the source voltage and appears not to be tolerant to reverse voltage either. Since the IC is measuring the voltage with +-0.5%…
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P-MOSFET allowed some reverse current, L7805CV destroyed. Why?

I was experimenting with reverse voltage protection using a P-channel MOSFET. I hooked up an IRF9510PBF in the following configuration (diagram from Nick Gammon's site, will change if requested): When I hooked up the 12 V power source backwards to…
piojo
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Reversing Polarity on Switch Mode PSU to use on Audio Equipment

I have a normal 12v 1amp switch mode psu. with positive pin, negative sleeve. I want to use it on a Roland ex3 s keyboard, which I got as a gift, but no power supply. The PSU specs match those of the Roland according to the manual. Is it save to…
Johann
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Rapidly reverse polarity of electromagnet

Please forgive my zero knowledge of electronics. I have asked my people what I thought was a simple question but I just get bogged down with endless questions which I can't answer. Expressing the situation as simply as possible. I wish to use a…
The Famous Cash
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Auto sun tracking relay wiring?

Ok here's a bullet list of what I'm working with • 1 5v DC 2 wire reversible electric motor • External 5v DC power source (battery pack) • 2 12v small solar panels ( for signaling left or right rotation) • 2 12v automotive dual switching relays Ok I…
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Reverse polarity with feedback

The below is a reverse polarity circuit with additional components around it. I would like to understand the exact functionality of the additional circuitry in dotted lines.
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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 array of n channel mosfets connected in paralel.…
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P-MOSFET reverse polarity protection, resistor and diode or not?

I have a PCB with a DC barrel jack, for which I would like to have a reverse polarity protection. The circuit exists in 2 variants, one with 5V input, the other one with 12V input, at 6A. Note I also have a TVS (SMBJ5.0CA or SMBJ12CA depending on…
user1532080
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4 6v batteries, with one connected wrong way round?

Today i was working on a machine with 4 6v batteries connected in series. It was in a building that was very dark and the batteries were covered in dirt and i briefly accidently fitted one of the batteries the wrong way around. After i corrected the…
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Want to reverse AC Motor direction - need help

I have this old Westinghouse motor it turns clockwise and I need counter clockwise. It has 3 leads at a junction on the rear, 2 line and 1 middle lead labeled 0. Anyone know how to help? It is a 110v 3/4 hp single phase motor model 89z123a.
Dlambe
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Reverse voltage protection: what is the function of C8 in this schematic?

I am reading about reverse voltage protection and I have found this circuit with its explanation but I do not understand why the capacitor C8 improves the behavior of the circuit when there is a rapid change in input voltage polarity.In adition, Is…
FranMartin
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Reverse voltage protection circuit explanation

Considering this circuit : (The complete schematic can be found following this link - page 23) It is connected on the return path of an IC to provide reverse-voltage protection. I understand that D11 zener diode set Vgs to 7.5V when Vdd is positive…
Loïc GRENON
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How to deal with extra pins on reversible connectors?

I want a header on my board to be reversible. The header has 4 UARTs, 4 power pins (VA,VB,VC,VD), and power (3V3) and PWM for a servo. The functions of most of the signal pins of the header are symmetric, so channels A,B,C,D become D,C,B,A if the…
bubbzilla
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What role does this diode play in this reverse voltage protector circuit?

I have been trying to understand this schematic, which is I believe intended to be provide reverse voltage protection. I understand most of the aspects of this. The basic idea is that D3 allows current to flow in the proper direction, which then…
Zefira
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