Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

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. ...

0
votes
1answer
45 views

Protect signal from noise in Arduino

I am trying to send a signal from the Arduino to a relay to open a switch. My problem is that my Arduino will be near the AC power lines. I searched for how to prevent the noise to ruin the signal ...
1
vote
0answers
46 views

power surge protection

I've seen power protection that uses: MOV (metal-oxide varistor) Inductor TVS diode Application Note: Transient Voltage Suppressors (TVS Diode) Applications Overview I didn't see any design ...
0
votes
0answers
30 views

How to connect led strip to be powered by charger and batteries part 2

Li-ion batteries are nominally 3.6V and three in series will not supply 12V very long if at all. You could use four series batteries and a 16.8V charger rather than 12.6V then add a 12V buck step ...
1
vote
3answers
42 views

How to connect LED strip to be powered by charger and batteries

I plan on using it mostly plugged in, batteries are there just for extra mobility and won't be used most of the time. Don't know lot about batteries so in first scheme I added a switch (pos. 1 ...
0
votes
2answers
52 views

How to measure output voltage of this Li-Ion battery circuit?

I've designed an AtTiny85 based Lithium-Ion battery protection/boost circuit that monitors the battery voltage and cuts the battery power to the external powered circuit when the battery dips below a ...
0
votes
1answer
32 views

De-rating / Re-rating criteria/theory for frequency in circuit breakers

I'm trying to spec a circuit breaker for a system that will be performing in the 3kHz range, and am not finding much info on how to calculate a new rating based on frequencies in this range (where ...
1
vote
1answer
35 views

Supercap overvoltage protection

I'm building a circuit where a supercapacitor will be charged over wireless energy transfer (basically two coils near each other). This means I can not guarantee the voltage feeding the supercap is ...
4
votes
2answers
405 views

How can I compare a TVS diode with a varistor?

For a 120Vac line protection element, comparing this TVS diode: With this varistor: The immediate differences I see are: The varistor is marginally cheaper The varistor specifies a maximum working ...
2
votes
1answer
65 views

Is the ESD and overvoltage protection for my ADC circuit sufficient?

I am currently building a data logging device for monitoring battery packs which contain 8 Lithium cells. The device will periodically log the voltages of all 8 cells, as well as log temperatures ...
0
votes
1answer
34 views

Exceeding Vmax rating of PTC Fuse

I am adding over-voltage, over-current protection in my circuit. My circuit/PCB has many DC-DC converters and these converters ...
2
votes
1answer
43 views

Safety Relay Circuit

I am looking for a way to add a relay-based safety feature to my BLDC controller. In case of an emergency the user must be able to push an e-stop (probably consisting of an NC contacts) completely ...
0
votes
0answers
45 views

Activated carbon face mask for protection against solder fumes?

What do you think about using a activated carbon face mask for protection against solder fumes as an alternative to using a fume extractor?
0
votes
1answer
40 views

Reasonable Li-Po Battery Protection Circuit?

I'm designing a circuit to monitor the voltage of a Li-Po battery (single cell 3.7v, 2500mAh, 25A) and switch off the battery when the voltage drops to a certain threshold. The Circuit will also ...
0
votes
3answers
78 views

thermal fuse as electrical fuse

I am trying to understand the spec of a Datasheet of a thermal fuse. for example the one below : https://nl.farnell.com/panasonic-electronic-components/eyp2bn134/fuse-thermal-cut-off-2a/dp/1832031 ...
12
votes
6answers
2k views

USB device with 2 ports - how to protect against user plugging in both

I've got a Full speed USB device which I want to provide 2 ports for - one each on opposite ends of the enclosure. This is so the cable can be connected wherever is most convenient. My MCU (atmega32u4)...
0
votes
0answers
24 views

Vector Shift for Islanding

I am looking to know how angle difference is accurately measured? Also why vector shift may cause issues with regard to loss of mains protection in distribution networks. Thanks
1
vote
2answers
119 views

Protecting yourself with latex gloves

Would wearing white latex gloves(doctor gloves) protects you from getting shocked when repairing electronics? And is there a reason why you seldom see anyone wearing gloves when dealing with ...
0
votes
0answers
36 views

Is there a Single Component/Chip for Performing Low Voltage Cut-Off for a NiMH Battery?

I would like to build a circuit that uses a single Ni-MH AA Battery. My circuit can work well with the 1.2v that the battery supplies most of its discharging time, and I would like my circuit to stop ...
0
votes
1answer
27 views

Protecting voltage sources against pushing or shorting into each other

I am designing a PCB where there is a load with peak power of 15 Watts to be powered from a user selectable voltage source. There are a 35V and a 24V sources and it should be only one of the voltage ...
1
vote
1answer
48 views

Measuring input voltage with 3.3V ADC MCU

I am designing my very first DC motor driver circuit. Right at the start, I want to be able to measure the input voltage to the system. The system supposed to work with external DC power supply from ...
0
votes
1answer
77 views

USB Broken problem

I have a problem with a device that I’ve built: It contains a LPC4300 microcontroller and it's supplied with 24V DC. I’ve noticed a strange problem when I connect it to a USB port. The device is used ...
0
votes
0answers
36 views

Chip(s) or solution to protect DC circuit with wide input voltage

I am looking for a solution to protect a DC motor control circuit with an input voltage of 12-55VDC from overvoltage, undervoltage, reverse polarity and overcurrent. Now, there are ICs doing just ...
0
votes
1answer
45 views

What will happen when taps at secondary side of auto-transformer are connected together (short-circuited)?

In case of Auto-transformer, there is only one winding, having three lead wires (1 for primary/input, 1 for secondary/output, and 1 common between both). At the secondary side (the output side), there ...
0
votes
1answer
22 views

Connecting a polyfuse (PTC / resettable fuse) without soldering

I want to connect up a polyfuse to protect a potentially flammable USB cable and a Raspberry Pi Zero in the circuit below. However it seems that most Polyfuses are supposed to be soldered and I'd much ...
0
votes
0answers
45 views

In circuit charging and transient voltage supression

I have a mixed signal board. Some digital components and a few transient generating relays and switches or potentially hazardous devices such as motor drivers. I have separated the voltage regions ...
1
vote
1answer
113 views

Full Load Amps vs General Purpose Amps

http://www.carlingtech.com/sites/default/files/documents/M-Series_Details_%26_COS_021114.pdf This circuit breaker have two different current ratings, depending on amperage range: Full Load Amps and ...
0
votes
1answer
54 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
votes
0answers
54 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
votes
1answer
41 views

Proper Flyback Current Protection Circuit for Variable Voltage Solenoid Driver

I am using a darlington buffered op-amp to drive a solenoid motor at variable voltages (for variable speeds of actuation). Here is my circuit as it is now: I am wondering which of the two flyback ...
0
votes
1answer
46 views

Car 12V Supplied device - Requirements

I am currently designing a device that is intended to be used outside the car and supplied by car 12V socket (also during the drive). The question is: Are there any specific requirements for example ...
0
votes
1answer
33 views

How to determine the right trip point of thermal cutoff for 1/4 hp 3A 115V single phase ac motor

The Thermal fuse blew in my Ryobi DP102L drill press motor, while I was drum sanding. There were no markings on the fuse. The single phase induction motor is 1/4hp 3A (no load) 1750rpm on 115V AC, ...
0
votes
1answer
51 views

A lot of questions regarding lithium ion power supplies and power regulation with safeguards

Per a members request I am making a post compressing multiple possible posts into one and providing additional info. I am making a 18650 powered portable electronics workstation that will have many ...
0
votes
2answers
70 views

What would be the safest method to power a laptop (IdeaPad 510 15isk) from a 14.8v battery pack?

Looking at my existing power jack and measuring it crudely with a cm ruler it looks like 3mm diameter x 1 cm length. The laptop bottom and charging adapter both say 20v @ 3.25 A max. What would be ...
1
vote
0answers
73 views

What fan could I use to extract hot air from an oven?

I am making an reflow oven. I've decided to use the picoReflow to do the job and monitor it. The oven is originally a lab oven, and it doesn't cool quickly at all. It has a vent at the top which I'd ...
0
votes
1answer
55 views

A question about lightning protection for a sensor mounted outdoors

There is an ultrasonic-windsensor which will be mounted on a bridge in winter. Maybe several of them. It seems like for outdoor use this device should be earth grounded(probably through mains earth? ...
1
vote
1answer
113 views

evaluating ESD protection for 3.3V i2c

Even though there are questions about ESD protection for i2c bus already in this forum, I wanted to ask how to suppress the clamping voltage of a TVS diode to a safe level. As an example, the ...
2
votes
2answers
108 views

16A Relay controlled with PWM

I am not very experienced with relays but I need to control the state of a relay with a PWM signal such that if the microcontroller is damaged and the controlling pin gets stuck in a high or low state ...
0
votes
2answers
40 views

What is the maximum charge current and discharge current of R5460 Series IC?

I am using "R5460N214AF" IC for 2 cell Li-Ion battery protection. According to datasheet, excess discharge current threshold is 0.2 V and excess charge current threshold is -0.2 V. I would like to ...
0
votes
1answer
41 views

Transfering configuration to IEDs using IEC 61850

Sorry if this is a dumb question, but since I don't have much experience with IEC 61850 compliant devices, I am having trouble creating the "big picture" of how the whole system is being configured in ...
0
votes
2answers
60 views

Current loop protection from wrong connection of the wires

I have built a current loop protection circuit based on the topic Using a microcontroller ADC to measure a 4-20mA sensor It works good. The next step is I want to protect the input of the circuit ...
0
votes
0answers
61 views

Changing values of a cheap ebay charger?

I ordered this charger from ebay https://www.ebay.com/itm/USB-1S-3-7v-Lithium-Lipo-Li-ion-18650-Battery-Charger-Charging-Protection-Module/323194353728?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=...
0
votes
0answers
81 views

Step up transformer protection

simulate this circuit – Schematic created using CircuitLab Hello, i have question regarding the short circuit current at both primary and secondary side of the XFMR2. Given the values in the ...
4
votes
2answers
198 views

Is this resistor necessary for protection?

I would like to incorporate this circuit in my design so that I could use a low current capacity slide switch to control the 2A current of a Li-poly. Now, I understand the purpose of having two PMOS ...
0
votes
1answer
87 views

Battery protection circuit

I’m trying to design a battery protection circuit for this 300mAh 3.7V LiPo battery. I’m an EE student which is designing his first pcb. Please forgive questions with obvious answers. My questions: ...
0
votes
1answer
61 views

Why does this LTC1440 Comparator switch so slowly?

I am trying to build an undervoltage protector for a 6S LIPO battery. My idea was to use a comparator to switch off an NMOSFET when the battery fell below a preset voltage, 20V: R20, R21 and C20 ...
0
votes
2answers
100 views

What kind of protection do these Ethernet “surge protection” diodes provide?

I was considering a network run outside of my home, and purchased a super-cheap "Ethernet Lightning Protector" because there was little to lose, and I wanted to understand its workings. Below you can ...
0
votes
0answers
86 views

Why are IDMT over-current relays used for the protection of feeders instead of inverse time relays?

IDMT - (Inverse definite minimum time) over-current relay. At first, I thought it was because of the inverse time characteristic of the IDMT relay, but then I remembered that inverse time relays also ...
1
vote
2answers
123 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
votes
1answer
181 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 ...
0
votes
1answer
85 views

unnecessary usb protection?

I have a device with two voltage sources and therefore I need atleast a diode on the lowest source to secure it. The lowest source is a 5V USB, and it is protected with a schottky diode with a 0.5V ...