*Your* health and safety while working on electrical devices, and designing devices that will not shock, set fire to, or otherwise harm the user of the device.

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1answer
47 views

What happens if there is a fault in the neutral wire between the grounding pole and the centre tap of the transformer?

I was reading through some SE questions/answers on residential power transmission and came up with two scenarios I'm unsure about: Assume that your house is wired properly (with no degradation), but ...
0
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2answers
44 views

Combining a benchtop power supplies

So I made an error when purchasing a power supply that was far below desired voltage (dc). The power supply I bought certainly produced enough current, however, and I am wondering if it is possible to ...
1
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2answers
83 views

Capacitor safety

After looking at some posts,I started wondering if using capacitors,especially electrolytic ones is as safe as I thought.After making sure that the you don't supply a bigger voltage than the rated one ...
2
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2answers
81 views

Can you protect yourself from Tazers by lining your clothes with aluminum foil?

It seems like you could protect yourself from a Tazer by having a conductive metal in your clothing that would complete a circuit between the two prongs with lower resistance than your skin. Since ...
2
votes
3answers
106 views

Phone travel charger for powering circuits dangers

I am thinking of using a phone travel charger to power a circuit.Ratings: input:110-240VAC(my outlet has 220volts) 50/60Hz 0,3A output:DC 5,2volts at 400mA The problem is that 220 V are of course ...
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5answers
4k views

Is it safe to connect an Arduino to the human body?

I want to create some project which uses an Arduino to collect and display ECG data. It uses two electrodes which are attached to the body (on the chest). The signal is then transmitted through ...
0
votes
1answer
64 views

Potential safety hazard? [closed]

Suppose one uses a poor 18650 (low quality and without a datasheet) to charge a phone and the phone tries to draw 3A-4A (2A @5V) from it. Would this be hazardous even with a protection circuit built ...
2
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0answers
48 views

Is there a good book on designing for electrical safety with AC mains power? [closed]

Is there a good book on how to design for electrical safety, particularly when using AC/mains power? I have look on Amazon without finding anything that seemed appropriate. This topic is largely ...
1
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0answers
31 views

Could a lipo/18650 overheat during discharge?

Suppose a cheapish lipo/18650 has a typical protection circuit in place, which, e.g., shuts off the battery when voltage gets too low, shuts off the battery when the current exceeds 4A, and prevents ...
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2answers
67 views

How to properly use ESD protection wristbands

I've looked at other articles on EE stack exchange about ESD precautions. I would like to use a wristband for precaution with microcontrollers. Where am I grounding my wristband to? Do I ground ...
0
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1answer
74 views

LED strip underwater

I am working on a project where a LED strip is placed at the bottom of a pool which will send patterns of light along the bottom of the pool. I have looked into some LED strips and found a 5V APA-102 ...
2
votes
2answers
34 views

Where can the detailed requirements for EU Low Voltage Directive compliance be found?

I'm designing an appliance that probably has to comply with the European Low Voltage Directive. I've been searching for a guide on how to design a product complying with this directive, but I haven't ...
5
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1answer
43 views

How does a fuse affect creepage reqirements?

I am designing a mains-powered device that has to comply with IEC 60079-15 (Non-incedive industrial eqipment). Creepage distances in this standard are inherited from IEC 60664, pollution degree 3. For ...
2
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2answers
56 views

Safety/efficiency of a makeshift aluminium can heatsink?

I had recently received a 9v 1A DC wall-wart off eBay, and needed to open it to swap the polarity of the jack to center negative. As I had the case open, my finger bumped against the metal part of the ...
4
votes
2answers
247 views

Hazards of puncturing lithium-ion batteries?

I was doing some electronics repairs, and accidentally punctured a small (mobile phone capacity) lithium-ion cell battery with a metal spudger. At first, I hadn't realised I punctured the batteries - ...
2
votes
2answers
109 views

Does any company manufacture American AC power plugs with insulated pins?

In Australia and some other places, good-quality AC power plugs have "insulated pins". This means that there is a short length of insulation covering the base of the pins. Darren Yates writes that ...
1
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1answer
51 views

Automotive power supply - considerations for selecting fuse

A power supply circuit for a device that runs off the 12V battery of a car, is shown below. simulate this circuit – Schematic created using CircuitLab LM7805 is used to generate a 5V ...
16
votes
2answers
661 views

Why are caps configured this way in EMC filters?

Every EMC filter I've seen has capacitors between the AC lines and earth, configured like this: simulate this circuit – Schematic created using CircuitLab Why are the caps not configured ...
-1
votes
1answer
51 views

What is a safe level of electromagnetic radiation measured in terms of received signal strength indicator (RSSI) e.g. -26 dBm?

We know that the laws of our countries set the regulatory limits of EM radiated power based on the EIRP transmit power of the antennas of devices. However, the received incident power is more ...
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0answers
53 views

0.8mm PCB for a PSU circuit

I am working on a PSU that converts 230 VAC to 12Vdc (0.1 A). The board has the necessary clearance and creepage distances. Would it cause any safety issue (IEC60950) if the 0.8 mm (or 1.2 mm) thick ...
4
votes
5answers
220 views

A “fuse” that blows upon liquid exposure instead of overcurrent?

I have a board that is mounted inside a waterproof housing, but occasionally the housings develop leaks and expose the internal circuits to water. This can cause unpredictable failures as the ...
0
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1answer
60 views

USB shield shorts battery… protect the PC?

I'm making a retro-fit device (so I have plenty of parameters that aren't in my control) where we're adding USB connectivity to the device for use with a PC. The device is battery powered, and the ...
-3
votes
2answers
110 views

When does a human body get shocked by electricity [closed]

Today I touched the live phase of the electrical line of my house wearing rubber shoes. However, I still got an electric shock As I wore rubber shoes it seems to me that I shouldn't be get shocked. ...
-1
votes
1answer
40 views

Is matching an infinite switch rating to a heating element required? [closed]

I want to use a Robertshaw universal infinite switch rated at 15 Amps to power a heating element to boil water in a stainless steel tub. The voltage is 240 VAC. A heating element greater than 3600W ...
0
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2answers
49 views

Creating small heater

I need to make a small heater. I was looking at this project: http://www.makeuseof.com/tag/make-your-own-temperature-controller-with-an-arduino/ but I need to design the heating element. I was ...
3
votes
1answer
48 views

Can a FELV circuit be connected to a SELV circuit?

This might be a very very simple question, but I'm unsure how to interpret the rules. I have a circuit which switches 230V using relays. The circuit is a motor controller for a motor control box ...
3
votes
1answer
86 views

Is a device with high voltage and low current safer than a device with low voltage but high current should you accidently bump into the +/- pins?

For example, my lead acid car battery is rated at 12 V/700 A, whereas my switch mode power supply has 250 V/6.3 A. If I were to accidentally bump into the +/- pins of either battery (forming a full ...
1
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1answer
50 views

Considerations when repairing dimmer switch

I originally asked this question on DIY StackExchange. So far no answers and a suggestion to try on Electronnics, so here goes: I have an IKEA lamp with dimmer switch which took a knock and ...
17
votes
5answers
6k views

Is this true: “At over 700 Hz, current simply flows over your body”?

I have heard this in a movie clip. I was just curious to know, is this really true? Because the one thing that I do know, is that at a high voltage, the current decreases, so that it doesn't harm a ...
0
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0answers
32 views

Portable Power Unit for 18V Power Input Device

Background I am experimenting with music mixing. I want to be able to record my music while "on the move", that is, not in the house, but in my car, so I can drive somewhere quiet and enjoy my ...
1
vote
1answer
53 views

Fuse rating and safety

Under what conditions would a faster, higher rupture capacity, higher voltage-rated fuse be less safe than the equivalently current-rated fuse which was slower, lower rupture capacity or lower ...
0
votes
3answers
218 views

Function generator as a DC power supply

I'm wanting to start my own lab at home so that I can learn things faster than uni teaches (we're not allowed into labs unless we're in our own lab). A friend said that I'd be better off getting a ...
10
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3answers
2k views

Mechanically damaged capacitor leaked liquid - is it toxic?

I have mechanically damaged a capacitor on an old motherboard and it made a PFFFT sound like some gas went out of it and then some liquid leaked. What is that? Is it toxic? I hope that it was not ...
0
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4answers
139 views

soldering protective gloves

Do you use any protective gloves while soldering? It has happened to me a lot that hot solderer touches my fingers. I am not sure if protective gloves would reduce freedom of my fingers for their ...
1
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2answers
81 views

what safety glasses

As far as I know soldering glasses are for eye protection against lead fume. As a personal experience I have observed some parts of lead with tiny explosion due to heat come out of lead with a smoke ...
1
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0answers
65 views

Safety/Quality issues by modding PC PSU to be floating.

Since I don't have enough money at the moment to purchase a good bench power supply, I want to 'mod' a PSU. In the first instance not by opening the PSU, but just by making an adapter that also puts a ...
1
vote
2answers
70 views

Computer Power Supply Testing Safety

I have a 750 watt ATX power supply that I will be testing with a multimeter to make sure the right voltages are present. How can I make sure that I do this safely? Is there anything that's threatening ...
0
votes
1answer
90 views

What is the current path when you touch the 230 V outlet?

The outlet's potential is 230 V, the earth's potential is 0 V. The person touching the outlet will get shocked, but why? What is the path that completes this circuit so current will flow?
9
votes
3answers
291 views

Is it safe to treat a system downstream of a reverse-biased diode as de-energized?

Suppose I have a 480 VAC line, feeding a rectifier and filter caps. Obviously this is not something to be trifled with while live. Now, suppose there are blocking diodes coming off the DC bus, as ...
0
votes
1answer
243 views

Transformerless power Supply - 24VDC, 120V AC and 230V AC

I want to know if it is possible to design a power supply for a circuit that can operate from DC and AC using the same input terminals. Thus, the output should be xxV DC (5-24 or whatever is decided ...
10
votes
7answers
900 views

Mains Voltage on Strip Board

I need to prototype something quickly as a proof of concept. Is it safe to use mains (UK 230V) on stripboard? It will be going to a transformer so I can control some appliance. Or should I design a ...
0
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0answers
33 views

Fuse header for GPIO pins?

I have recently gained interest in electronics & tinker with Arduino & Raspberry Pi. But I made some big mistakes & ended up frying my board with mains AC supplied to the GPIO :( (yes, I ...
0
votes
1answer
80 views

How to wire a RCBO/GFCI correctly (in series with the upstream RCBO/GFCI)?

For one of my projects, I need to add a RCBO/GFCI for the protection of the users. I know that there is a RCBO somewhere up the chain, therefore I am facing a confusion: there is a non-zero resistance ...
5
votes
1answer
103 views

Electric shock from laptop due to capacitive coupling?

If a person touches an exposed wire (the wire has a ground-prong) on the 20V side of a power cable while barefoot, I heard that it is possible to receive a shock of higher than 20V due to capacitive ...
1
vote
2answers
331 views

By touching neutral why we do not get shock?

According to Benjamin Franklin, current flow from +ve to -ve terminal. But after Joseph Thomson's discovery it was conceived that although current flows from +ve to -ve electrons flow from -ve to +ve ...
6
votes
4answers
1k views

Which are the safety recommendations for soldering?

I was reading about tin alloys for electronics soldering and found it it has about 40% of lead in composition. Lead, everyone knows, it's very dangerous to breathe it due to being a heavy metal. Also, ...
1
vote
1answer
91 views

Transmit electrical signal across human body [closed]

Is it possible to transmit and receive an electrical signal SAFELY using the human body as a medium? For example, I would have a transmitter of some sorts in my left hand, and a receiver in my right. ...
1
vote
2answers
64 views

Getting UL certification for neon signs

I make neon lights and have been for 10years on my own and just recently found out that I could get in alot of trouble for not having my signs UL certification done. I want to make it right and want ...
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3answers
89 views

Using A Relay To Control A Lamp

I'm experimenting with capacitive sensors acting as switches and want to actually give my circuits some practicality. I've been researching how to use relays with microcontrollers (in my case, an ...
1
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3answers
45 views

Boost converter safety during debugging

When I was debugging my microcontroller-based boost SMPS I accidentally got 85V (instead of 15V as I intended) across the 1kΩ test load resistor. Does this spell a hazard for the one debugging the ...