Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

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.

18
votes
10answers
7k views

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 ...
2
votes
2answers
9k views

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 ...
5
votes
1answer
570 views

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 ...
10
votes
2answers
7k views

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 ...
15
votes
5answers
11k views

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 ...
3
votes
1answer
923 views

What component is represented by reference designator GT?

I can see that G represents a generator/oscillator, and T represents a Transformer, but what does GT represent?
0
votes
1answer
929 views

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 ...
5
votes
2answers
124 views

±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 ...
4
votes
2answers
4k views

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 ...
3
votes
1answer
1k views

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 ...
2
votes
2answers
336 views

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 ...
1
vote
2answers
9k views

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 ...
5
votes
5answers
3k views

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 ...
4
votes
2answers
56 views

±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 ...
3
votes
3answers
5k views

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 ...
2
votes
7answers
2k views

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 ...
2
votes
2answers
2k views

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 ...
0
votes
1answer
982 views

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 ...
5
votes
2answers
9k views

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 ...
3
votes
2answers
3k views

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 ...
3
votes
3answers
1k views

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: - +12V (connected to 50W source) ...
3
votes
3answers
681 views

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 ...
2
votes
1answer
3k views

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 ...
2
votes
3answers
2k views

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....
2
votes
3answers
4k views

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 ...
2
votes
3answers
3k views

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 ...
1
vote
1answer
118 views

Rs-485 isolation

Hi, I have RS485 communication circuit as shown in figure. But it has no isolation, only SM712 is used for ESD protection. Now, i think it will be better to isolate the it.So, how can i isolate it? ...
0
votes
3answers
1k views

How to build Li-ion over-discharge protection board

I have an Arduino board with a pump attached to it, and for powering both, I'm using a 18650 battery cell with a DC-DC Boost Converter. I plan to leave it working even when I'm not home, and I know ...
-1
votes
1answer
102 views

What purpose does the following circuit have? [duplicate]

The circuit was pulled from a SBC schematic. VBUS_5V is the input power from the micro USB port. Ultimately I am attempting to figure out if there is current limiting between VBUS_5V and VDD_5V.