Questions tagged [surge-protection]

Questions about protecting electrical devices from voltage spikes.

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Can I use a normal diode as a Zener/Varistor ? If not, why not? (focus on Varistor use)

When I look at a normal diode graph like that I see the Vz Zener voltage of it looks just like a Zener, so why not using it reverse biased like a Zener? I ask like that because I never saw it being ...
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Use of multiple earthings for single installation

For a home electrical wiring, is it acceptable to have to multiple earth rods on different (reasonably apart from each other) locations? In good practice, to keep earth resistance low, we use multiple ...
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protect from in rush current of buck convertor

I made a PCB base on the following schematic, it uses a buck convertor for 12 to 5 v and then uses an LDO for 5 to 3.3 to run my ESP module I use 2 P-channel MOSFET for polarity protection , but ...
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Active clamp for high side N-channel driver

Most similar thing I found is this: How is an active output clamp implemented on a high-side MOSFET switch? where it does that with a P-channel MOSFET and it's the usual clamp with polarity swapped. ...
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3 answers
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DC over current protection idea needed for step down converter input

I ride an electric motorcycle which is powered by a 26s 96V Li-ion battery. It has regen braking that charge the battery with 50A current. All the lights are powered by a 60v-120v to 12V 15A DC step ...
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Varistor derating chart reading

I am studying TDK document about varistor selection but I cannot understand how to read the derating curve. The Imax I got is different from that mentioned in the document. In Figure 20 of the ...
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Thermal dissipation on TO-252-3 Package

I am in the process of designing a surge stopper with fault latchoff using LT4356. https://www.analog.com/media/en/technical-documentation/data-sheets/LT4356-3.pdf I decide to use this MOSFET, which ...
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Does an eFuse exist that latches off immediately (and does not reactivate) in case of a short-circuit?

I've just discovered eFuses (from Texas Instruments + Toshiba + STMicro). In case of a short-circuit on the output, MOS can be disabled in 150-500 ns by detecting a surge of current (called "fast-...
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Might I use a diode to block current surge from slowing DC motor (instead of using a battery to absorb that current/energy)?

Hi people - I'd like to bounce this off some fellow engineers/gearheads... I've built a turntable system to add to my Shapeoko 3-Axis CNC machine. The idea is to turn the machine into a CNC lathe of ...
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EN61000-5-4 Surge protection of PCB

We are developing a household device, which consists of a +48VDC power supply and a PCB, where everything is located inside a grounded metal frame. The only parts that come out of the metal frame is a ...
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Will a parallel diode across 24Vdc line be effective for relay coil surge relief?

In our factory, a controller malfunctions many times. I think, it's becuase of relay coil open surge (24Vdc line, Coil 350mA per each). So, I put the schottky diode across the DC24V Line in parallel. ...
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How to connect a TVS diode

I want to use a 824021 TVS diode in my circuit. The input is 5V and the clamping for tehe TVS diode is at 7V. Which of the following two connection diagrams is correct A or B? Or a better way to put ...
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AC overvoltage protection using Zener diodes (and some other things)

I am considering building an AC protection circuit using the following schematics. I am a physicist and have little practical experience with implementation of electric circuits. Looking forward to ...
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1 vote
3 answers
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How to find the lightning protection of a TVS diode?

I am using a STmicroelectronics ESD diode SMAJ58A-TR, which has a surge protection standard of IEC 61000-4-5, but they have not mentioned the value like 4kV, 6KV. While checking in datasheet they have ...
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Can a normal diode like 1N4148WS use for voltage suppressor?

Currently, Im building a solar mppt charger circuit from LTC4013 Analog devices. Here is the datasheet: LTC4013 datasheet Here is the schematic that Im working on: I have a confusion on the diode ...
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Gauging surge protector outlet capacity question

I'm planning to use an 80A power supply (or two 40A ones) for multiple addressable LED strips. Each strip is max 90W, 20A. I want to use a single surge protected power bar for them, however they are ...
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Crack in surface of varistor, likely bad?

I experienced a power surge at my house and some equipment stopped working. one device just had a blown fuse so I soldered in a new one and it worked fine. Another device had an obviously blown ...
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How to best protect 12V from voltage transient spikes?

I am building an AC power supply and I decided to put digital current and voltage panel meters into it. I have an issue where whenever my main contactor engages and disengages, there is a transient ...
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How to add surge protection and over voltage protection for a smart switch SMPS

I am making a smart switch for toggling appliances with a 10 A relay using esp8266 as my MCU. I am using an isolated 3 W (5 V, 600 mA) SMPS. I have seen in some specifications about 2.5 kV surge ...
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1 answer
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How does the ground electrode in a three pole gas discharge tube work?

I'm developing a surge protection circuit with a three pole gas discharge tube (I used this one.) When I apply the AC power source (220V 50Hz) sometimes the fuses were blown but rarely. I know it's ...
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14 votes
2 answers
5k views

Suicidal ASUS power brick?

I was playing around disassembling an Asus laptop power brick (19V, 4.74A) and came across this strange arrangement in the circuit, where just after the bridge rectifier, there is a MOSFET (Q1, N ...
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Problem when using gas discharge tubes in surge protection circuit

I am working on a surge protection circuit. My schematic is shown below. In this design, I used 3 poles GDT 350V DC spark (this one) over at the beginning, followed by some varistors (V1, V2, V3, V4.) ...
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1 vote
1 answer
155 views

Why does switching OFF heavy electric loads cause a surge in voltage?

A voltage surge is a higher-than-normal voltage that temporarily exists on one or more power lines. Voltage surges are normally caused by the switching OFF of heavy electric loads. I know that most of ...
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Ethernet Surge Protector Speed

I've been investing in some new surge protectors lately – a fraught process at best given the difficulties of comparing model and brand quality. Things were even trickier when looking into ethernet (...
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7 votes
1 answer
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Difference between ESD and TVS diode?

What is the difference bweteen TVS diode and ESD. Though both of the functions are the same, which do we need to choose for what application?
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1 answer
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RJ11/RJ45 power surge protection

I have a case where phone landline is above the ground and when lightning strikes it hard, the internet modem and router gets damaged, including devices connected to it. I was wondering what would be ...
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2 votes
1 answer
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Supply turn-on voltage spikes - best practices for protection

The problem I recently had a situation where a board had a destructive fail event from turning on a 53V battery which appeared to have had a voltage spike at least over 80V, most likely well over 100V,...
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1 answer
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Blade Fuse Properties?

I am sure you have seen automotive 'Blade' fuses. They are special fuses constructed to protect equipment that is DC powered. I have asked around and determined that a 125v DC rated fuse is more than ...
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1 vote
1 answer
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Buck- Boost converter failed on surge at 500volts

Basic Technical Details The driver is basically a DC solar charge controller, it's used in solar street lights, it requires a battery and panel. This driver uses the Buck-Boost Topology. At night it ...
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2 answers
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How to prevent an electrical motor surge from repeatedly blowing the fuse when it stalls?

So, this is something that I shouldn't need to do, but I do. As far as I understand, it should be trivial, bit I'm hazy on the details. I have a 2kW mains AC power tool with a rotary output. Its ...
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1 answer
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How to design a discrete flat-clamp TVS circuit

I need something similar to the Texas Instruments TVS3300 but for a higher voltage. The TVS3300 is basically a drop-in replacement for a TVS diode that clamps the voltage using an internal mosfet and ...
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3 votes
0 answers
58 views

Protection against constant overvoltage from power supply

I have a project using USB VBUS as power source. Fault to protect from: a bad AC-DC 5V adapter goes haywire, or a USB form factor device with non-5V output (some laptop AC-DC with USB type C?), or ...
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0 votes
1 answer
234 views

Load dump protection on a 48V EV

We're building a device that would take power from the output of BMS in a 48V Electric Vehicle (EV) (2/3 wheeler) with say a 0.5 to 2 kW motor. We are planning to use a buck regulator with Vin max of ...
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2 answers
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MOV failed due to lighting or OV on power line Feeder control

we have a filed failure of our product which is feeder controller as shown in below image. It installed in metal box. we have tested our feeder stand alone at 15KV surge and it compliance with 15KV. ...
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0 votes
1 answer
55 views

Inrush Surge Limiter [NTC Thermistor] on Primary or Secondary side of Linear Power Supply

In designing a linear power supply, I understand I need to limit the inrush surge current on cold start, to charge up the large bank of filter capacitors, post-rectifier. However, my original intent ...
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2 votes
1 answer
54 views

Non-isolated DC-DC converter for power supply and equipment at remote location (on top of a tower)

I am designing a DC-DC converter system for powering equipment in remote locations (on top of a tower.) Each device needs 150 W of power. I designed DC-DC converter both at ground-level power supply ...
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0 votes
1 answer
120 views

Neon bulb lamp replacement for surge suppression

I'm restoring an HP 141T and it has a broken neon lamp which is used I believe as surge protection in the following configuration: On the right is the CRT. I believe the only purpose for such lamps ...
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0 votes
1 answer
94 views

Circuit Protection to the current circuit

I have a basic circuit that uses 555 timer to generate PWM signal and the PWM signal turns the high side switch, SI1865DDL, on and off at certain frequency and duty cycle. The output from the high ...
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1 answer
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Does a TVS diode provide adequate protection for an LCD screen powered from a car 12V outlet?

I fitted an LCD screen in my car and I want to power it, along with other devices, directly from the car's battery. The other devices are specifically designed for automotive use, but the screen, a 10....
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0 votes
1 answer
150 views

Will these 100 ohm resistors protect my GPIOs from power surges?

I am designing a circuit for a microcontroller that has a few 3.3V GPIO pins. I heard from somewhere that adding small resistor of around 100 ohms in series with the GPIO, will add some additional ...
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gdt and mov surge protection

greetings fellow engineers, i came by to ask you for help, i'm building a circuit that needs to be as resistant to surges as possible. I did my research, and make to this circuit: as it is supply by ...
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1 vote
0 answers
12 views

Coupled current in shield in a tube from a transient surge

If a shielded cable (B) is running inside the centre of a tubular structure (A), how is the coupled current from a surge estimated in the shield? I am trying to figure out how the coupled current ...
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2 answers
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Help in assessing the input mains circuit integrity

I've been working on designing a (220-380 VAC) 3/4 wire phase energy meter and in terms of metrology operation, things were working very well quite similar in terms of metrology if compared to a ...
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11 votes
3 answers
3k views

What would it take to make a PS/2 keyboard interface hot-swap?

A long time ago, I had to service some of the early Compaq Desktop PCs. They used to have fuses on the motherboard that blew when a customer hot-plugged a keyboard. I found this when googling on the ...
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1 answer
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What surge/lightning protection is needed for an elevated off-grid solar security system?

I have a semi-urban hunting location that I would like to monitor remotely. I have an elevated (~20ft) box blind I am installing off-grid solar system (specs below) in. The purpose is to power a small ...
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2 votes
2 answers
116 views

Surge protection in power supply

I am building an RS485/modbus controlled device for sensing AC current and switching on/off AC loads. The schematic is given below. 5V DC power for the device and RS485 bus connection are provided ...
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1 vote
0 answers
121 views

Circuit protection with TVS and polyfuse

I have a 36V system that has to be protected against 1000V surges as described by IEC61000-4-5. Some SMC TVS diodes are rated for this exact purpose and are able to conduct the surge pulses without ...
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2 answers
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Do I need to insulate down conductors in a lightning protection system?

When we install seperate down conductors in an external lightning protection system, do we need to fully insulate it or need to insulate in touchable areas? Is there any requirements in IEC 62305 ...
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1 answer
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Voltage surge suppression technique in high-speed switching based electronic circuit

I am working on a circuit that transmits ~1MHz sine wave(20V amplitude) in RLC based circuit scheme, also transmits high-frequency signals(pulses(non-periodic)) ~20MHz(10 %DS)(20V) in a CR-based ...
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1 vote
1 answer
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What could be causing my APCs to buzz from time to time, and for my Tesla to stop charging? [closed]

I have two issues happening at the same time (very much related). The APC brand UPS backups in my office all start buzzing at the same time, then click once every 5-10 minutes. This happens at all ...
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