Skip to main content

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.

Filter by
Sorted by
Tagged with
0 votes
1 answer
29 views

Arc fault receptacle or Arc fault breaker [closed]

When year did they start using the NTC in the ARC Fault breaker or AFCI receptacle?
Michael 's user avatar
0 votes
0 answers
67 views

AFCI outlet AFCI GFCI breaker [closed]

What style NTC is being used in an AFCI outlet or AFCI breaker? I can’t locate it.
Michael 's user avatar
-4 votes
0 answers
70 views

revision of prior post as to why mosfets fail question here with a drawing of circuit as requested [closed]

i am mainly referring to mosfets of the 90's mainly rated at voltages 200v and up and amps of 1amp and above with gate capacitance in range of .1 to 333 microfarads. it does not seem to be dependent ...
user158293's user avatar
1 vote
2 answers
88 views

How to protect a motherboard from an old power supply? [closed]

I have an old Taiwanese Senstron ST-41 (TAO YIN-TCY6 94V) power supply from 1987 used in an Apple 2 clone with DC outputs: 5V 5A 12V 2.5A -5V 0.5A -12V 0.5A Is it possible to add extra protection (...
Anton Andreev's user avatar
0 votes
2 answers
69 views

ADC pin protection when using external power supply

I was playing with ADC on ESP32-C6 (devkit board) trying to read values from photoresistor (VT90N2) in voltage divider with another (10K) resistor. simulate this circuit – Schematic created ...
valeroso's user avatar
2 votes
1 answer
38 views

1 Cell LFP Battery Pack Protection

I am starting a project that requires a single 3.2V LiFePO4 18650 cell to be in a housing with exposed contacts, suitable for easy swapping in and out of an unpowered device. The device will only be ...
zambetti's user avatar
2 votes
1 answer
95 views

What are the purpose of these components on my car ECU?

What are these metal "cages" around the capacitors as seen in the circuit below (2x).
wgthompson's user avatar
0 votes
1 answer
26 views

Does the unidirection TVS diode like SMAJ15A be used on DC lines to protect the IC or Converters from negative Peak, clamp down to -0.6V?

Most of the DC- DC converters have absolute maximum down to -0.6. If bidirectional TVS diode is used then negative peak cannot be clamped near to -0.6v, in this is the case can we use the ...
Raviteja Cherukuri's user avatar
1 vote
1 answer
71 views

Building a DIY BGA Rework Machine

simulate this circuit – Schematic created using CircuitLab I am trying to build a DIY BGA reflow machine. I have a very crude schematic, but the idea is run each of the 6 heating elements in ...
MacAttack1's user avatar
1 vote
1 answer
56 views

Identify smd component ( p_j89 ck)

I have electronic board of level switch device. I have a problem in it a found an element it seems like a diode but I need its data sheet to find a replacement for it because it is short circuit in ...
Abdelrahman Esmat's user avatar
1 vote
1 answer
44 views

Adafruit Feather M4 CAN Express overvoltage protection

I would like to read CAN signals from my car over the OBD-II connector. My question is, whether I need to implement any kind of (overvoltage) protection, so the Adafruit won't get harmed (and vica ...
Zsolt's user avatar
  • 11
1 vote
3 answers
140 views

Damaged ATMEGA328P despite clamping diodes and current limiting resistor

I have a custom PCB designed to interface an Arduino Nano's ADC pin that had 12v from a bench power supply inadvertently connected to a header pin meant for 5v input. The ATMEGA328P now gets extremely ...
Robert Susmilch's user avatar
0 votes
0 answers
37 views

Battery powered IoT lightning sensor shielding

I have a low-power wireless solar powered IoT sensor that has a Geiger counter (400V SBM20 tube) on board and is controlled by ATmega328P, sitting outside. This set-up has been working great for ...
bobnecat's user avatar
0 votes
1 answer
60 views

Is a buck-boost converter good enough as circuit protection for an automotive application?

I am designing a circuit for a automotive application that requires a stable regulated 12V supply. The supply in turn must be powered by an automotive battery. I am currently looking at using a ...
Jayson Okhman's user avatar
0 votes
0 answers
23 views

Does a buck-boost converter serve as enough circuit protection for an automotive application? [duplicate]

I am designing a circuit for a automotive application which is meant to map voltage ranges between two airflow sensors (i.e. 1 sensor has an output range of 1.75-7.0V and I want to replace it with a ...
Jayson Okhman's user avatar
0 votes
1 answer
64 views

What circuit protection devices are needed for an automotive application? [closed]

I am designing a circuit for a automotive application which is meant to map voltage ranges between two sensors (ex. 1 sensor has an output range of 0-5V while the other has a output range of 1.75-7.0V)...
Jayson Okhman's user avatar
1 vote
2 answers
492 views

Needs help understanding this breaker: Chint NB1-63 C50. Confusing (63 or 50)

I'm trying to understand information on this AC breaker.(See picture) Is this Rated for 50 amps or 63 amps? Does the "C50" stand for Current? If you think it's 50 amps, how do you know this?...
RayLoveless's user avatar
1 vote
1 answer
63 views

Advice on using limiters for circuit protection in HF circuit [closed]

I am designing a receiver amplification circuit and I'd like some advice. We operate in the 10-20 MHz range, and in proper operation receive input signals on the order of -35 dBm. Our current RF chain ...
Theo's user avatar
  • 11
0 votes
1 answer
64 views

Is it better to shut down an overheated laptop? [closed]

My brother and I were sitting beside a laptop. He was playing a game and we noticed the laptop was overheating. My opinion was to turn it off ASAP to prevent "Thermal runaway" and other ...
Michael George's user avatar
0 votes
0 answers
56 views

OCP protection circuit

simulate this circuit – Schematic created using CircuitLab I wanted a project to learn stuff and test my own skills, so I started to design a DC electronic load. For this project I imposed ...
Pierpaolo Sicignano's user avatar
0 votes
1 answer
81 views

Will voltage at the inputs/outputs destroy an unpowered opamp?

I have a circuit powered by 12V that accepts an input signal of 0V to 10V. The circuit shall act as a buffer to the signal, with an added LED indicator. In certain circumstances, the circuit itself ...
one_three_three_seven's user avatar
0 votes
1 answer
38 views

Robust 24V alternator input circuit

I need a bit of advice on the following proposals for interfacing an industrial mining truck's 24VAC alternator signal to a micro. The frequency is DC to 1khz. The voltage varies between 5 and 24V ...
Pieter Potgieter's user avatar
0 votes
0 answers
39 views

Plugable Varistor and Fuse Cartridge for easy and safe replacement

As I have concluded with some tests, by reading some posts and even asking a question on this forum, Varistors can get damaged with multiple or even just one cycle of use. They fail as a short, being ...
Dinis's user avatar
  • 73
0 votes
0 answers
75 views

Protecting negative power rail

I don't trust my power supply and want to protect my circuitry from over(under)-voltage, but cannot find a clear path of going forward with negative power rail. LDO which I use (LT3094) is rated for ...
Andrejs Cainikovs's user avatar
2 votes
1 answer
110 views

Apparent contradiction in op-amp datasheet

I'm building a high-voltage regulator whose error amplifier is an op-amp. I'm relatively new to op-amps and currently using cheap single-supply LM324 so mistakes don't cost much. The error amplifier ...
Joe's user avatar
  • 199
0 votes
2 answers
61 views

How to select ESD TVS diode? [closed]

This is the following specification of my circuit Vin 8V to 32V The breakdown voltage should be 33V of TVS I don't know what clamping voltage means please simplify it for me What should be Vc?
Monesh Rathod's user avatar
1 vote
2 answers
87 views

How to protect a device from reverse polarity and over-voltage?

I am designing a device that will include a DC power jack. There is an external wall adapter that converts the 110-230 VAC from the mains to 20 VDC. Here is the schematic: I intend to use a standard ...
uz3il's user avatar
  • 317
1 vote
2 answers
73 views

Intrinsic safety (IEC60079-11) - assessing spark ignition of RLC circuit, but the L is placed before the zener barrier

My IS circuit contains an inductance, capacitance, and resistance. Shown below is the simplified schematic, with uncountable and countable fault applied, resulting in the most onerous condition: The ...
Never's user avatar
  • 100
0 votes
2 answers
96 views

Surge Voltage Protection

I am currently working on designing a protection circuit for mains power. However, as a hobbyist rather than an expert, I am seeking assistance with this circuit. During my research, I came across an ...
M-125's user avatar
  • 53
0 votes
1 answer
92 views

Simple overvoltage protection circuit (LED indicator modification)

I saw this overvoltage protection circuit from theoryCIRCUIT. I was wondering if instead the LED indicating that voltage continues to flow, we could instead make the LED turn on when overvoltage ...
HuracanWind's user avatar
1 vote
2 answers
71 views

Any way to remove the voltage impulse of DC motors, both ways?

I'm attempting to make a circuit for controlling the direction of a DC motor by comparing two photo resistors, so far i managed to make the logic of swapping polarities, amplify the output and connect ...
Kristian Filimpocher's user avatar
0 votes
1 answer
82 views

P-MOSFET Circuit Breaker trip detection

I am using a 15 A circuit breaker. To detect the trip, I have designed a P-MOSFET based circuit. The idea is to connect the load signal of circuit breaker to the gate of MOSFET, which is pulled down ...
Deepak Reddy's user avatar
0 votes
0 answers
30 views

Reverse polarity, over-voltage and over-current protection for a "breadboard add-on board"

I am designing a small utility board that should attach to a breadboard and take power from it. It can be described as the opposite of this SparkFun Breadboard Power Supply: instead of powering the ...
tpimh's user avatar
  • 513
0 votes
3 answers
147 views

Issue with solenoid valve sparks despite using two 1N4001 flyback diodes [closed]

As a student, I'm currently working on a science project where I intend to connect a 12V, 2A solenoid valve to a relay and subsequently to a Raspberry Pi Pico. The solenoid valve is powered by a 12V, ...
Tanmay Sonar's user avatar
1 vote
0 answers
48 views

Protection considerations for powering a microcontroller circuit through USB-C/Micro-USB

I am working on a project which utilizes an Adafruit ESP32 Feather V2 microcontroller and has a bunch of components requiring 5V. I will have everything on a perfboard and to power it more easily, I ...
mhmarcush's user avatar
0 votes
2 answers
67 views

How is live-plug in (hot-swap) different from regular powering ON of a module?

I fail to understand the difference/challenges between the two situations. Plugging a unit (or circuit card) to a live backplane. Vs Plugging it to a dead bus (or inactive power supply) and then ...
Dynamic_equilibrium's user avatar
0 votes
1 answer
92 views

Cutoff circuit with bipolar transistor

I'm trying to build a cutoff circuit with a PNP bipolar transistor (TIP42C) and a TL431A. R1 = 2.2k R2 = 11k R3 = 220 R4 = 4.7k The circuit should allow the current to flow when the voltage is above ...
TheInterestedOne's user avatar
0 votes
2 answers
96 views

What is it about LEDs and resistors that makes it so order doesn't matter? [duplicate]

For reference: I was trying to figure out why I can put a resistor before or after an LED for it to work. I found an answer here that says: The LED only sees the difference in voltage between its two ...
JVDS1069's user avatar
0 votes
0 answers
11 views

What does the graph 'Short circuit monitoring interval Vs time' mean in this SSR data sheet?

In one of the Panasonic Solid State Relay (SSR) datasheet,the short circuit behaviour is as shown below : If short detected- > Trip the relay -> Periodically retry untill the fault is cleared. ...
Dynamic_equilibrium's user avatar
1 vote
1 answer
67 views

Protecting parallel loads

I have a project that has two separate sections that must be powered from the same power source. I do not know the resistance of said loads, but I know the power supply that each of them on their own ...
Ciro García's user avatar
0 votes
1 answer
77 views

Negative Voltage Cutoff

How do I turn off a negative voltage supply using a Zener diode as well as transistors and resistors? Let's say I have -30V supply, but I wanted it to turn off at -15V (using the zener voltage as a ...
HuracanWind's user avatar
0 votes
0 answers
54 views

High negative voltage cut-off for op-amp from dual-rail power supply

In the picture I have a circuit that prevents reverse polarity and cuts the voltage with respect to the Zener diode (15 V) as a voltage reference for positive voltage output. How do I apply the same ...
HuracanWind's user avatar
0 votes
2 answers
97 views

Not able to correlate the graph and table for the I2t rating in a fuse datasheet

In the datasheet, the I2t rating of a 5A fuse is 0.055 at 10 times In. Using the same value to estimate the trip time for the 10 A condition, I get 0.0022 seconds. In the graph below, it comes ...
Dynamic_equilibrium's user avatar
0 votes
0 answers
42 views

What do the following parameters indicate in a resettable fuse?

I am not sure how to decipher the Pd and R1max info in the below datasheet. Does PD indicate the tripped state power dissipation or maximum power dissipation under non-tripped operation? If you ...
Dynamic_equilibrium's user avatar
1 vote
0 answers
34 views

How to design for Transient Immunity especially for IEC61000?

I'm working on a PLC project wherein I've to design the protection for transient immunity tests as per IEC61000 standards. I checked in the net regarding deign for EFT,ESD and Transient voltages. I've ...
Anil Suha's user avatar
  • 101
1 vote
1 answer
102 views

How to design short circuit and reverse polarity protection for PCB?

I have read many posts and articles about short circuit and reverse polarity protection design for a PCB, but still I am quite confused about the industry standard/common principles here. The ...
eidetech's user avatar
1 vote
0 answers
135 views

Oscilloscope input clippers

The analog front end of an oscilloscope begins with an attenuation stage. Mostly they use two attenuation stages, like 1/1 and 1/50. From: Rigol Homebrew Wiki - schematics page The image above ...
Ahmet Atcı's user avatar
1 vote
1 answer
88 views

Arrester 'minus' connected to the 'plus' of a capacitor

I am repairing 'Siemens SITOP power 20' power supply. I have to draw its circuit to better understand it and a notice a bizarre design decision. Can you help me to understand it? It has an arrester ...
Gleichmut's user avatar
  • 131
1 vote
1 answer
124 views

Add common mode noise into existing circuit

I have a complex 24 VDC in circuit that I need to demonstrate fault cases as a result of potential common mode noise due to a floating earth on the PCB. As such, I am interested in the best way to ...
MrTea's user avatar
  • 113
2 votes
3 answers
413 views

What happens when you get a fault to earth without an MEN link on a 3 phase generator? [closed]

For context, an isolated type single phase generator (no earth stake or neutral-earth link) had a residual current device connected to it and then a fault between active and earth was placed on the ...
SS1's user avatar
  • 89

1
2 3 4 5
15