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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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41 views

What is Metal Oxide Varistor (MOV), meaning of its specification and how it protects circuit from over-voltages?

Hello, I have a circuit in which a voltage source is connected to some sort of RC Load. To protect this circuit , there is an Metal Oxide Varistor (MYN15-681K). The Pics of circuit and datasheet ...
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0answers
50 views

How to protect a buck DC-DC being backfed from the load (e.g. a battery as a load)?

Background I want to design a DC-DC adapter that is foolproof and has some protections in place so that it doesn't accidentally damage the somewhat expensive equipment downstream. Here's what I have ...
0
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1answer
47 views

Can high power USB destroy older devices? [duplicate]

My brand new pair of bluetooth headphones stopped working after charging them with a 2.1 Amps USB outlet. I can't turn it ON anymore. I do see the LED battery Green then I charge it though. I noticed ...
2
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0answers
48 views

High power / high current clamping circuit

I am looking for ideas on how to clamp high energy surges in the input of a high current / high power system. The input to the system is 24V. During steady state, the system sources 85A of current ...
0
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3answers
80 views

What can happen with the PCB foil while SMD resistor destructive overheat?

I need to protect the gate driving circuit by putting the resistor between the gate and the control circuit: During the testing of the mockup MOSFETs can go be destroyed which leaded to high voltage ...
0
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1answer
35 views

One-time fuse for disconnecting/breaking signal path

I am looking for an IC solution, ideally, but alternatively also could use a tiny circuit that would allow to accomplish the following feature: Trigger an event by MCU that will fuse-out/disconnect ...
0
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1answer
42 views

How to fuse batteries connected in parallel?

I have two GEL batteries 12V/130Ah and want to connect them together in parallel. Currently I have one battery in the system and it is fused on the positive wire before the isolation switch. I ...
0
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1answer
28 views

Integrated Circuit Epoxy Outer Molding [duplicate]

I'd like to know whether flame retardant epoxy resins, the FR-4 brominated type for instance, are used in the outer molding for integrated circuits or whether it's just a plain epoxy resin. ...
0
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0answers
58 views

ATX Power Supply trips with DC Motor

I am using an ATX switching power supply as a power source for my motors and air compressor. Specifications of the PSU is: Type: ATX 12V Model: 850UB Vac~ input: 230V, 5A, 50Hz Vdc MAX DC Output: ...
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0answers
32 views

Tp4056 overcharging

I have combined five 18650 cells in parallel and i am charging them using a single tp4056 circuit . The problem i am facing is that the module keeps on charging. I had to stop the charging manually at ...
1
vote
2answers
52 views

protection of industrial analog input modules for high-voltage signals

I'm looking at ways to design a multi-functional analog input that can take both voltage and current inputs for industrial applications. The voltage signals are in the 0-40V range and the current ...
0
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1answer
33 views

Do i need to protect a DC adapter from current spikes (produced by buck converter)?

I wonder if i need to protect my ac adapter, which has over-voltage, over-current and short-circuit protection. The ac adapter feeds a buck-converter which uses a low-side n-mosfet switch ...
1
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0answers
47 views

TVS protection burnt too easily

It's about an year that I'm using TVS diodes to suppress spikes from the AC motors (240V - max 240W) that drives my roller shutters and protect the solid state relay that actuate the motor. What is ...
1
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1answer
58 views

Bypassing DSLR battery to power camera from power supply cheaply with bidirectional optocouplers

I am trying to power my Nikon DSLR with a permanent power source instead of the battery for long captures (overnight) without buying the overpriced battery adapter. I can't simply connect a AC-DC ...
1
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3answers
66 views

Is it necessary to add fuse protection (at the inputs) when using multiple DC-DC converters?

I would like to know if it is necessary (or recommended) to add fuses at the inputs when using multiple DC-DC converters. I have attached a quick schematic to illustrate what the design would look ...
1
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1answer
57 views

Powering module directly from LiPo Charger with LiPo connected

I have a GSM module (Particle Electron) which has pins for powering it from a LiPo battery. The pins accept voltages from 3.6V to 4.4V. The module can also be powered from 5V supply through another ...
1
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2answers
47 views

Can an array of fuses protect a PC port from damage?

I'm paranoid right now because I made another circuit meant for the parallel port of the PC. While all my previous experiments involving the port were successful (except for one experiment I made a ...
1
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2answers
70 views

Protecting microcontroller output

I'm designing a very simple microcontroller breakout board. I wonder how can I protect microcontroller output pins against accidentally connecting another signal to one of them and burning the pin's ...
0
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1answer
97 views

Microwave oven with no heat, Bad design or wrong component choice? [closed]

Few days ago, my Magic Chef MCD990B microwave oven magically passed away randomly and so suddenly that I didn't even have time to say goodbye, not that I have used it heavily or considered it as my ...
0
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1answer
140 views

How do I protect an electronic circuit

I’m beginner in electronics and i have project for grow LED light and i want to connect LED with timer. My inquire how I protect my circuit. My circuit Adapter 12V 1.2A Timer (5-20v) up to 5A 2 * ...
0
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1answer
58 views

Multiple DC power source to the board protected by schottky diodes

Provided is the DC power supply block to the micro-controller development board from one of the leading MCU manufacturers. I need help to understand this arrangement. I will use two sources V5-...
3
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0answers
92 views

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 ...
0
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1answer
99 views

12V 12A resettable crowbar circuit

The idea is to protect the input stage of a control card from improper power supply connection. The power supply is a standard desktop AC-DC power adapter (Meanwell GST160A12) with inbuilt shortcut, ...
5
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1answer
258 views

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 ...
0
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1answer
56 views

Earth& neutral voltage detection

Can someone suggest me circuit to detect the earth to neutral voltage. I would like to trip relay coil using microcontroller if earth to neutral voltage exceeds 3v. There are device RCB and RCBO ...
1
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3answers
104 views

Not understanding why in overcurrent protection only a certain section will isolate (why not the whole system)

I'm having an issue understanding a simple concept for faults. I understand the principles of how the relays cause the circuit breaker to open etc when a larger current goes through them to provide ...
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2answers
116 views

How do protection circuits deal with instantaneous voltage?

For protection components such as Varistors and Diodes, when an instantaneous fault voltage is applied - how to do these devices protection before the device has time to conduct. For example, a ...
0
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1answer
102 views

DW01 2s protection

I want to protect 2 18650 batteries with single DW01. The problem is how to increase the protection voltage on DW01 . I have read that I should use voltage divider on VCC pin. I just want to make sure ...
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2answers
102 views

How to calculate the exact delay of a delayed ON/OFF imlemented by low pass filter

I am trying to implement a delayed ON/OFF by using low pass filter implemented by a capacitor and a resistor. I can find the R,C, and cut off frequency by using calculators I found in the internet. ...
1
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1answer
95 views

Protecting against reverse polarity

I'm building a JTAG programmer for the old Motorola 56k devices and I want to add some circuit protection before having some boards built. I'm more of a firmware/digital guy, but here's what I came up ...
0
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2answers
132 views

Protecting microcontroller digital output pin from ESD, reverse connection, and other possible user error

I want to protect an output pin from ESD, reverse connection, and other possible user error that might cause damages to my circuit. This pin output pulses depend on the amount of water passing through ...
1
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1answer
64 views

Opto-coupled EIA-422 receiver (understanding suggested circuits)

I am looking at a standard for communication of marine electronics (NMEA). The standard is electrically essentially EIA-422 but it prescribes opto-coupled differential receiver pins without connection ...
1
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5answers
78 views

Using battery to operate a DC load

FOLKS, am a learner. This is the problem am trying to get around. what would happen if I use a 200amp 12V battery to run a dc standing fan of say 2amp power draw or a piano of same rating or any ...
0
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0answers
96 views

What are good alternatives to the dw01a used with TP4056?

Currently I have a 18650 battery charge and discharge circuit in my Board design as a "Emergency fall-over power. And I have some problems with it. First problem I see is that while the battery is ...
0
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0answers
30 views

TVS Diode Response

I am trying to understand what would the response of the TVS diode be when I will apply +5V and -5V across the device. From what I understand is that when I will apply +5V and Ground across Pin1 and ...
3
votes
3answers
1k views

Circuit breaker vs fuse timing

Recently I powered on an electrical device that was (unbeknownst to me) quite defective. It tripped the circuit breaker almost immediately (after shooting off some sparks). There was a small (600W) ...
3
votes
3answers
147 views

History of ESD protection

These days you can't read anything about electronics without hearing about the dire consequences of omitting ESD protection from your designs. It seems this wasn't always the case. If you look at ...
0
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2answers
72 views

Arduino NANOs sharing input signals and controlling Pixel Ring blowing up

We're a bit stuck on the following problem : We've connected a bunch (18 to be precise) of Arduino NANOs on the same +12V supply and they all share the same PWM output from another device (which goes ...
1
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2answers
122 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 ...
0
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0answers
37 views

How can I build my own over voltage protection circuit up to 480 VAC

I am rigging up a portable test panel, will be using a true-meter APM that will do up to 600 VAC or 600 VDC. I would like to be able to use it to measure typical U.S. 120 VAC or 240 VAC and 480 VAC. ...
0
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1answer
18 views

TPS2559 TI, current switch for circuit protection

I'm researching a current limit switch but I am a bit confused. I need an IC that works as a current switch. I have a battery with charging and protection at one end, and buck boost on the another. ...
1
vote
1answer
75 views

GPIO input protection

I know this subject has been covered but I have a specific question regarding zener characteristics for microcontroller GPIO protection in vehicles where nominal voltage could be 12 or 24VDC. ...
-1
votes
1answer
54 views

Using diode to protect controller input

I'm looking to use inductive proximity sensors on a Duet Wifi (3D Printer Control Board), the board itself runs 3.3v but the sensors require 12-24. I've asked this on the product forum and they ...
0
votes
1answer
231 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 ...
1
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2answers
44 views

One PSU powering one high power device & one low power device

If one was to power a (potentially) multi-amp device and an arduino with an external LM7812 12v voltage regulator to a 19v laptop charger (in parallel), would the arduino be safe when the multi-amp ...
0
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2answers
87 views

Bypass Capacitors - Why do they not provide voltage spikes back down the line?

I am new to electrical engineering. Please excuse me if I use the wrong terms. (Welcome to correct me tho ;-) ) I am learning about capacitors, and I have been studying a circuit diagram explaining ...
0
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1answer
72 views

Wondering if my protective diode is sufficent

First off, since this is my first post (I am a long time answer seeker), I would like to thank the SE EE community for all the answers I got here over the years! Thanks! Being self-taught, I've ...
0
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1answer
82 views

Diode advice (charge & drain circuits)

I have a charge & a drain circuit connected to a Li-ion cell. As only one circuit can be connected to the cell at a time, I believe I need some diodes. My questions are about when the drain ...
3
votes
3answers
103 views

How to protect againt surges if working and maximum voltage are too close

I have a circuit that I want to protect against surges and eventual peaks (e.g. indirect lightning surges) and I was thinking about TVS diodes or MOV. The situation is: -My circuit input is 48V that ...
9
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5answers
2k views

Why aren't starter circuits protected?

In most cars and trucks, a thick cable connects the battery directly to the starter (solenoid). Why don't these circuits have have any kind of overcurrent protection? It is an accepted practice ...