Questions tagged [surge-protection]

Questions about protecting electrical devices from voltage spikes.

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33 views

How to pass the IEC61000-4-5 using TVS?

I want a surge protection for my board to pass the IEC61000-5-4 class3. I don't know how I can find which TVS is appropriate ?
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1answer
27 views

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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44 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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49 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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2answers
56 views

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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18 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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1answer
37 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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1answer
40 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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1answer
82 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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1answer
68 views

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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1answer
81 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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47 views

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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11 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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2answers
52 views

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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3answers
2k 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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1answer
50 views

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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2answers
67 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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41 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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2answers
109 views

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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1answer
68 views

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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1answer
79 views

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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61 views

Lightning arrester sharing earthing with surge arrester

Is it ok for lightening arrester and surge arrester to share common earthing - that is, to use a common wire and electrode? Is it OK for the lightening arrester earthing electrode to be close (1 or 2 ...
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1answer
57 views

Capacitive voltage drop - surge and safety

Background I'm designing a power amplifier and I want to sense power-drops early, in order to properly shut down the class-D amplifiers, SMPS's and save status in the microcontroller, before brownout ...
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1answer
47 views

ESD protection for power input with several fused branches

I'm designing an industrial board that will be powered with a +24V DC. On the PCB there are several fuses to protect each branch against over-current/short-circuit. Example: simulate this circuit &...
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1answer
65 views

How to protect low-voltage hardwired device against 120 V AC miswiring ? (I need a resettable solution)

I need to protect a hardwired device, made for AC low-voltage transformers (e.g. doorbell), from miswiring to a 120 V AC power line. It actually occurs no matter how many warnings I put everywhere. ...
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129 views

H-Bridge current limiting

I am designing a simple H bridge circuit for use with the Atmega8 microcontroller. The DC motor moves this application a lot and generates 140 mA current spikes (DC motor locked) or 60 mA with normal ...
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1answer
76 views

Why does wiring to a surge protective device need to avoid sharp bends?

Here is an excerpt from some Schneider Electric installation instructions for their QO2175SB 240V single phase "SurgeBreaker" SPD: NOTE: The SPD ... must be installed as close to neutral ...
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1answer
63 views

How does common mode voltage surges couple in wires

From doing some research and with the assistance of a user on this platform, I would like to know if my understanding of this concept is correct. Please note this post is an add-on to this post. A ...
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1answer
34 views

surge protector when device turned off [closed]

Can a voltage spike hurt a plugged-in device even if the device turned off? (e.g. an air-conditioner that's always plugged but rarely in use) And if so, would you recommend installing surge protector ...
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4answers
106 views

Is there a device to prevent a main circuit breaker from tripping and give an added layer of protection?

I would like to install some additional appliances in a room that already has a couple of heavy equipment machines running in it. These are sensitive machines, so instead of having the main circuit ...
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3answers
328 views

Discharge risk of an LED fade-in circuit

The simplest incarnation of the fade-in circuit I have planned is simulate this circuit – Schematic created using CircuitLab This gets a time constant of ~2.7s before taking into account the ...
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4answers
657 views

Should I buy a diode with higher maximum ratings if it costs the same?

I need a diode that prevents surge currents from a DC motor flowing back into the power supply. The motor draws a continuous of 10A at 12V. Was checking a store for a rectifier diode and found out, ...
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3answers
79 views

How do I test grounding/lightning protection?

I manage IT for several clients in Central Florida, where we have quite a lot of lightning (the most in the U.S.). I have one client that has trouble keeping electronic devices alive. We have replaced ...
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1answer
49 views

Can this schematic protect my load cell/strain gauges from lightning?

Today I was soldering gas discharge tubes (GDTs) to one of my PCBs used in a column load cell. I found the placement of the GDTs very odd as the main aim of GDT is to protect load cell or strain ...
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3answers
354 views

Power supply add-on to sink current

I have 10A lab PSUs at work of which most don't support sinking current (they shut down on overvoltage). The sinking time I need is typically very short: a few A for less than 1 second, the time it ...
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1answer
38 views

5v / USB standalone surge protection? Buck/boost boards? [closed]

Not an engineer, but relatively handy. This is just out of my depth on what is possible (and hopefully, commercially available) I had a 1/4 second brownout/blackout that fried all my wyzecam v2 (I ...
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48 views

Can anybody guide me how to protect an IC from air arcing at high voltage test?

I want to check the isolation voltage of an IC by applying high AC voltage up to 10kV across the primary and secondary sides of the IC. During this process, I am facing a problem of air arcing above ...
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1answer
66 views

1-2 second home power loss: some circuits stay powered - computer doesn't turn off. How is this possible?

We've been having some local power outages which last for about 1-2 seconds and maybe at times are only 500ms. I've noticed that we have two computers which stay powered and I'm trying to figure out ...
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1answer
48 views

Metal Oxide Varistor connection

How do I select the MOV for a multiple operating voltages. Consider the diagram below, when switch is in position 2-1 and 5-4 (both primary winding are connected in series), I can apply an input ...
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2answers
90 views

How do TVSS and Circuit Breakers (thermal-magnetic) interact with each-other?

In EU you can find thermal-magnetic circuit breakers all other the places in buildings and it's not uncommon to have daisy chains of them (meaning a main panel will have one, which is connected to ...
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50 views

Type 1 surge protection: parallel or series?

Type 1 surge protection devices (SPDs) are installed at the outside edge of electric service, usually between the power meter and the meter base/socket, and protect the entire house. But how do they ...
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1answer
68 views

How to choose TVS/ ESD for sensitive application?

I am using ad8232 ECG with 3 electrode configuration, Edited ad8232 used schematic I need to protect circuit from any voltage more than 5V, since ecg measure only around 300mV with common mode signals....
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5answers
3k views

Can lightning strike into the phone line damage electronics in the house through the ADSL modem?

I was always wondering about the following: If lightning strikes directly into the phone line outdoors, can the excess power coming from the phone line jump over the switching power supply of the ADSL ...
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1answer
103 views

Protecting circuit input against lightning - how to put all the pieces together?

I am designing a single wire (ground return) telephone for use in our hobby caving expeditions, starting out from a well known and successful design called Michiephone (http://speleonics.com.au/...
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2answers
372 views

Difference between placing unidirectional TVS diode before fuse or after P mosfet

In the buck-boost converter I am finishing, I came out with this question. At Vin (12V in my circuit) I place a 7A fuse and a P mosfet (IRF5305) to prevent reverse polarity issues. Because I want to ...
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1answer
43 views

Are TVS diodes necessary if device is not grounded? (i.e. portable)

If I'm working on a battery powered device that has no connection to ground, is it still necessary to guard against voltage spikes?
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52 views

What is the RMS current going through this fuse?

I'm chose a fuse to for a transformer, and now I'm trying to calculate the cross section of the cables. I'm using the following formula: Where Tk is the protection time, Ik the short-circuit current ...
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56 views

lt4363 - 2 Surge Stopper: Shutdown / MOSFET Gate and Vout

Good day everyone I am currently working on the board which uses a Surge Stopper LT4363-2. Without LOAD the circuit works fine but once I use LOAD and force a SHDN to low with a Temperature sensor The ...
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1answer
34 views

Relays for switching circuilation pumps

I have a board populated with Omron relays (G5Q-1A4-EU DC5) and I want to use them to switch circulation pumps (https://imp-pumps.com/pumps/ghn/). Is the previous relay appropriate to be used with ...
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1answer
450 views

TVS diode for RS485

I'm studying the ISO1500 for an RS485 application. In particular, I'm looking for a TVS diode for bus protection. I've found that a common TVS diode used for RS-485 applications is the SM712 (like ...

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