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Questions tagged [protection]

Ancillary circuitry added to a design that provides protection of the main circuitry to enable the main circuits continuing functioning. In some cases the protection circuitry is sacrificial, being destroyed or degraded in the act of protecting. But not all protection circuits may do this. Examples of faults protected against are: Overvoltage, ESD, overheating, Overloading (too high of a current draw) amongst others.

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A device used to logically turn on a circuit with voltage being the input parameter

I’m working on a project which utilizes a power-source which is liable to vary. I have a micro-controller sitting at the output of an LDO (Low Dropout Regulator). I’m concerned about the LDO ...
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Polyfuse with Crowbar for Over Voltage

I am looking to add overvoltage protection to a circuit of mine. A standard way of doing this is with a crowbar circuit with a fuse to blow when tripped, thus disconnecting the circuit. However, I ...
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ITS4060S-SJ-N overvoltage protection

I (think I) want to use an ITS4060S-SJ-N (+datasheet) in a circuit that can't handle over 40V (an LM2576T-5), but will normally receive 8-30V with a ≤12W load. Its purpose would be to provide ...
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Protecting back to back mosfets

I'm designing a high side back to back common source bidirectinal power switch made from n-mosfets. schema: Schematic attached. The questions: How can i protect driver from voltage spike from ...
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Dual N-channel mosfet Rdson value

I'm going though datasheets of some dual N-channel MOSFETs for li-ion battery protection, like 8205A or ECH8695R, for some thermal and power dissipation calculations. There are Rds(on) values, like ...
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What is the purpose of this 5 V protection circuit?

I'm working in the OEM company and I want to know what the purpose of the below circuit is. Whether +VCC5V0 or -VCC5V0, Q8 is off so I don't know the purpose of this circuit. It should be a ...
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95 views

Protected 18650 batteries shut down after I introduce a capacitor to the circuit, why?

I have a 24V audio amplifier that is powered by 8 packs of 6x protected 18650 batteries connected in series to produce 24V, and then all the packs are connected in parallel. The amplifier powers a ...
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Which type of electrical protector is better for the appliances? surge or over/under voltage protection? [migrated]

I decided to buy a electrical protector for appliance in out kitchen. There is two options and I'm confused and cannot decide witch one is preferred for me and witch problems can harm devices easier. ...
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Inrush Current effect on a Relay

I am confused about inrush current for a relay. For example, if I had 12A as the inrush current due to a motor, if the contact rating of a relay is only 6A, does a new relay need to be chosen? As in ...
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37 views

Need help understanding DALI circuit and 220 VAC protection

I am making a circuit to interface my MCU with a DALI bus. My basic circuit works and I am able to communicate on DALI bus. It looks like this: I fully understand the above circuit. After my base ...
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29 views

ADC Measurement on Automotive Circuit with Arm MCU

I'm trying to develop a circuit capable of measuring voltage on 6 different automotive pins at 12V nominal. I'm hoping to use the integrated SAADC in the nRF52832. I've done some research into ...
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1answer
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Identification of a protection IC

I need to find a replacement part for a burnt IC. It is placed between a MCU and some exposed IO. It was burned by applying 12V as input when 3V3 was the absolute maximum rating in the datasheet of ...
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How to prevent someone clone PIC [closed]

ACT 1 Okay I know there is code protection system on PIC. But it is preventing someone read the code, not copy. It looks still easy to clone and run on another circuit. Can you suggest another ...
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37 views

replacing a lithium ion battery protection circuit

I read several other postings regarding BMS's but as this is my first attempt to use them and I guess it can be a fire hazard choosing the wrong part, I'm going to ask: I have a battery-powered LED ...
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22 views

Reverse polarity protection LiFePo4

I'm doing a project with esp32 devkit v4 and I'll be supplying it with external power (LiFePo4 3.2V cell). I want to do a protection in case the battery gets connected inversely. I searched about it ...
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Circuit diagram question - microcontroller input protection

I'm new to electronics, and I would like someone with more experience to look at my diagram. The circuit consists of: a 5 V regulator (from a 12 V input) that powers the microcontroller a pull-up ...
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P-Channel MOSFET reverse polarity protection on NMOS array chip

I'm trying to achieve reverse polarity protection for the TPL7404LADR chip which is basically an updated version of the ULN2003 darling transistor array. To do this I want to use a P Channel MOSFET ...
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Disadvantage of using a Schottky diode across the LDO input/output for reverse voltage protection

I'm studying a linear power supply circuit design for my future project and I started off disassemblying a good(expensive) LPS out in the market. While I was studying it, there was a part that I wasn'...
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how to make an ESD sensitive circuit?

I have an experiment where I plug a sensor to an ESD (Electrostatic Discharge) protection circuit. Sensors are very expensive and very sensitive to ESD. I have tested my protection circuit it is ...
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1answer
55 views

Protecting RS-232 from overvoltages

I am using Some arduinos (5V Pro-Mini, but planing to move to actual ATMEGA chip) over a distance of few metres. These are connected using standard Alarm cable (I had problems with Ethernet cable and ...
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57 views

Smart undervoltage protection

what is the simplest way to regulate the min DC voltage in a circuit? ...
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2answers
205 views

Pre-amplifier input protection

I am building the Velleman K1803 pre-amplifier kit. This amplifier has a maximum input signal of 40mv. The audio input to the pre-amplifier will be a piezo-electric sensor, and this can certainly ...
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Motor-side of BLAC supply goes into overvoltage when regenrative braking using an LM5060

I am currently using an LM5060 for protection of the motor supply on my BLAC motor driver. Everything works well until I decelerate the motor quickly, this makes the supply voltage peak above the OVP ...
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1answer
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Protective-Earthing the chassis with the earthing point being the star-point - How does it keep the Chassis at Earth potential?

I always understood that one of the two purposes of protective earthing is keeping the electric potential difference between the chassis of a devide and the ground (the ground I am standing uppon ...
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150 A 12 - 16 V DC Short Circuit Protection

I am powering a ROV from a 4S LiPo battery (12.0 V minimum, 16.8 V maximum). The resistance of the battery is 36 mΩ, so that a maximum current of 470 A can flow through a short-circuit. In order to ...
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57 views

voltage transient protection for MV Motors

What types of transient voltage protection is applied on medium voltage motors and are these types of protection that are applied depended on the type of motor it is e.g Synchronous vs Induction motor?...
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1answer
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How does this isolation transformer protect user from transients/mains?

I'm looking at a pretty simple overvoltage/transient protection circuit designed to protect users but I don't understand what the transformer is doing. The circuit is designed to protect the output ...
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1answer
67 views

Device for preventing 12V battery from dying

I am looking for a device which cuts off the connection between batteries and the system just like a circuit breaker when my 12V battery goes below 9V(for example) for preventing it from dying ...
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2answers
33 views

How to check protection circuit in lithium battery

I've recently bought a single cell, 600 mAh lithium battery (like this one) and a TP4056 battery charger module, which I intended to use with the battery. The charger has an integrated protection ...
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1answer
45 views

Protection for transistor driving a coil

I recently purchased a few electromagnets. I want to drive these with transistors, but I want to build in protection, as these don't have any available specs re: max operating temp, duty cycle, etc. (...
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1answer
43 views

RTD circuit in industerial application

I'm trying to design RTD measuring for industrial use which has EMI/EMC/ESD. I have 3 wires input to the board. obviously 3 wires out of the board are going to 3-wire configuration PT1000 1- 3V3 (...
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2answers
57 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 ...
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2answers
127 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 ...
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1answer
91 views

MCP73871 Battery Under Voltage Protection

I want to use MCP73871. Is there a battery under voltage protection in this charger IC? or may I use a battery protection IC? Answer for @Bimpelrekkie I decide to use my power architecture as ...
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1answer
134 views

Cause of high failure rate in SC189 buck regulator

I have a small board that uses the SC189C buck regulator to take 5 V down to 3.3 V. For whatever reason somewhere between 25% and 50% of these boards have had the voltage regulator fail at some point, ...
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65 views

What is the difference between these two protection circuits?

I have seen both protection circuits used in various designs. The first just back to back diodes clamping a line, the other clamping the line to the system voltage rails. Whats the difference between ...
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1answer
117 views

Mosfet Gate-Source Zener [closed]

I want to confirm this circuit is going to work and ask how to calculate the zener voltage. The load is going to be driven by 30 volts, and the gate voltage is the same 30v, through an optocoupler.
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1answer
130 views

Op Amp input protection

I was looking for an Op Amp input protection circuit and the most common I found looks like this. When the voltage at Input Signal goes above/below Op-Amp's supply ...
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1answer
41 views

Need help finding an under-voltage protection IC for 2-4 cells [closed]

I've been looking for the last few days but I just can't find one. I've found a ton of single cell protection IC's but I can't find one that does the same for up to 4 cells. A stackable single cell IC ...
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2answers
88 views

Mains AC overvoltage protection using a TRIAC

I am trying to design a circuit that protects 127V appliances if plugged in a 220V socket (in Brazil 127 and 220V sockets have the same shape and it's easy to plug a 127V appliances in a 220V socket ...
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1answer
69 views

Input protection on a DC jack

I am designing an battery powered instrument with around 20-40Ah 3S li-ion batteries in it along with a 10A 3S(12.6v) external charger. Due to ease of availability and the current capacity I have ...
0
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1answer
43 views

How do I choose appropriate fuse for my circuit?

I am currently using a AC-DC adaptor with specs: AC-I: 100-2040V~50/60Hz 1.6A DC-O: 12V 5A Which is powering up 8 DC motors, 4× 12V 6W 4× 12V (wattage not specified, the motor is meant to be ...
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2answers
129 views

How does diode clamp protection work?

I am not able to understand how diode clamp protection works. Considering the diode clamp protection as shown in Figure 1: When the input voltage (Vin) becomes more than power supply voltage (Vss = ...
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1answer
45 views

Power Consumptions of GFCI Outlets and GFCI Breakers

Due to my applications, I need to know the ballpark power consumption of the internal circuit of a GFCI receptacle and GFCI breaker. Has anyone measured them? Could they reach above 5w or 7w?
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75 views

Protecting analog pin from ESD strike

After reading some relevant questions on ESD here, I have come up with the following approach to protect some ADC GPIO pins on my lipo battery operated board that are open to external input, thus ...
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1answer
51 views

Circuit protection component arrangement

I was reading this thread and decided that in general it's better to place the reverse polarity protection diode D2 after the TVS rather than before it, and to instead use a bidirectional TVS for D1 (...
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54 views

GFCI contacts with two solenoids

I've finally understood the purpose of the second solenoid in the above GFCI. How it works is when Reset was pressed. The contacts come to the top (attracted by the top solenoid). And in the second ...
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Low Side Mosfet protection circuit

I build a current limiting circuit, which clamps the current to lets say 4A. Id like to add a mosfet protection, which copletelly turns off the power mosfet, if Drain - Source is higher than 6V. In ...
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1answer
72 views

Voltage sampling from 220vac to 5vdc

I made a 1 phase to 3 phase inverter using arduino and IR2104 to control the speed of an induction motor and it is working perfectly. To complete the protection scheme, I need to monitor voltage of ...
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1answer
71 views

Leviton GFCIs constantly trip on shaded pole motors

Update: I consulted with other electrical engineers. Here is a plausible mechanism. Again refer to the circuit diagram of this GFCI: Look at the board layout. There is a long trace from where C3 is ...