*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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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 ...
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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 ...
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0answers
27 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 ...
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1answer
34 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 ...
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3answers
81 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 ...
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2answers
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 ...
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4answers
96 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 ...
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2answers
67 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 ...
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0answers
61 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 ...
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2answers
58 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 ...
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1answer
87 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?
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3answers
284 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 ...
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1answer
104 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 ...
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7answers
845 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 ...
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0answers
29 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 ...
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1answer
48 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 ...
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1answer
78 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 ...
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0answers
128 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 ...
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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, ...
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1answer
71 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. ...
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2answers
54 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
75 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 ...
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3answers
38 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 ...
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3answers
98 views

Why is this person shocked?

The voltage over the person is 250V. Why does he receive a shock? Doesn't the earth have a very big resistance so the current will be very small?
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2answers
41 views

Operate Arduino Nano using variable voltage

How safe/dangerous is it to operate an Arduino Nano 5V with a varying voltage source? I have a circuit that provides a duration of power with a starting voltage of 5.3V and an ending voltage of 4.5V. ...
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2answers
70 views

Is it necessary to have insulator sheets between PCBs and antistatic mats?

I am recommended to use some insulator or paper sheets when testing PCBs on antistatic mat connected to ground via antistatic wrist band. Is this correct way. Why is it necessary to have insulator ...
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1answer
76 views

Do soldering glasses protect eyes from capacitor explosion

I am concerned about safety while working with electrolytic capacitors. Can I use soldering safety glasses to protect my eyes while working with electrolytic capacitors?
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7answers
9k views

Can a bird, previously at earth potential, get electrocuted by landing on a powerline at high-enough voltage due to the initial “equalization charge”?

At the voltage levels of typical overhead transmission lines in the US, a bird can land on one and be just fine (as long as it doesn't do something like spread its wings and touch a tree or something ...
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3answers
105 views

why does the model s use multiple batteries?

The Tesla Model S and NASA's Robonaut both use a battery pack that consists of an array of hundreds of battery cells. Why don't the engineers just create one giant cell?
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1answer
126 views

Wi-Fi controlled light; 230VAC - 12VDC/3.3VDC

I try to connect an ESP8266-12 and a 12V RGB LED strip to 230V AC. Based on this link, I've came to the following scheme. This will also be the first time I will etch a PCB myself. The partlist will ...
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1answer
55 views

Use a steel welding table to ground yourself from electrostatic discharge (ESD)?

I have a large steel welding table that I have been using as a work station to solder together my own custom PCBs. I have been using my anti-electrostatic discharge grounding bracelet and connecting ...
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2answers
312 views

What happens if you put the connector of a live charger in your mouth?

So what exactly would happen if you put the connector of a plugged-in charger in your mouth? I am sure it is a bad idea but can it really hurt or even kill you? Some posts on social media led me to ...
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2answers
121 views

Can I use a 25 meter LED stripe with a single power adapter?

I have 5 stripes of 5m length and 300 RGB LEDs (type 5050) each. One LED consumes about 20 mA at 12 V. Therefore, my whole 25m setup would use about 30 A. Is it safe to connect the 5 stripes series ...
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2answers
115 views

Plugging in an oscilloscope in a land of non-grounded outlets

Background: I have only one outlet in my house that remotely approximates a proper equipment grounding conductor (it's bonded to the mains ground point via the armor of 50s vintage AC, which is better ...
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1answer
96 views

Are small clay capacitors pose any health hazards?

I'm making a small activity with children where we will be using capacitors and resistors to make jewellery like earrings. Do they contain any materials that pose a skin or otherwise health hazard?
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2answers
591 views

Multimeter into wall sockets

If you placed one of the multimeter's probes into the hot slot of the wall outlet and touched the other probe to your skin while grounded, for example to some dirt outside, would you get bitten by the ...
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1answer
118 views

Ground impedance monitor circuit design

I'm trying to design a ground impedance monitor. The idea is that the equipment in question needs to disallow operation if the ground wiring is disconnected or the connection is poor quality. This is ...
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1answer
94 views

Class II isolated power supply (wall wart) — referencing the output to mains neutral?

If you connect the - terminal of a Class II (isolated) wall-wart-type power supply to the neutral of the mains circuit feeding the wall wart, will that cause any damage or hazards that I should be ...
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6answers
2k views

How To Know If a Fuse Will Work Properly?

I want to know what kind of periodic test we use to test if a current-limiting fuse will normaly open and protect an electronic circuit (a battery charger) if a failure occur (short circuit or over ...
0
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1answer
53 views

Using a ferroresonant regulating transformer as an isolation transformer

I'm looking to use a (surplus, NOS) Sola (catalog number 22212) ferroresonant voltage regulating transformer (120V primary and secondary) as a low-power isolation transformer (4A) in case I need to ...
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4answers
153 views

Providing house wall switches with 3.3v/5V supply?

It's a bit non-technical, but I'd love to hear the opinions of the pros. I'm trying to figure out what is the best way to connect my home's wall switches (lights, etc.) to 3.3V/5V. The plan is the ...
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1answer
68 views

Safety in a capsense lamp

I'm playing around with the idea of adding a capacitive sense switch to an all-metal lamp, and have some questions around safety as I'd, obviously, prefer not to turn the whole thing live. In the ...
0
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1answer
69 views

Rewiring a 12V charger

I have a Windows tablet with a charger which crapped out. The old charger was 12V / 1.5A - fairly standard but it had a rare tiny pin connector. Rather than buy a new charger, I decided to cannibalise ...
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2answers
87 views

Can I use aluminum tape or naked two paralleled striped cables to connect parallel LED strips?

I need to parallel connected couple dozen cut LED strips. The total current reaching them won't exceed around 2 amps. My constraint: I can not order any more components for the job. My tools: ...
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2answers
74 views

Building a prototype rig with naked boards and wires (running 24V, 3.6 A): how to be safe?

I am building a prototype rig. It includes: 1) A "naked" 24/48 V motion control evaluation board. 2) A I=3.6 A stepper motor. 3) A power supply. I wired up the motor to the board with four wires (A-, ...
0
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1answer
131 views

Resistance Wire Circuit Safety Around Water

I'm working on a project that requires heating of a copper pipe with water running through it. I'm aware that this is a common issue by itself but as there will be people working around the system ...
0
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1answer
90 views

What is the maximum voltage of a Lithium Ion Battery

My question is about the maximum charge voltage of a Lithium-Ion cell. I have charged my battery pack with 8.4V (the maximum voltage). The pack is a Samsung ICR18650-26F. The pack has a smart ...
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1answer
82 views

Safety when charging two LiPo cells in series

NOTE: I am asking this question because I am new to this subject, and I want to be sure about what I'm doing before I go out and buy parts. I am making a really fancy watch with an OLED screen, ...
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2answers
442 views

I just blew a capacitor. Now what?

We worked two years on and off on this project at my friend's place. Finally we finish, I take it home. There's a power supply unit but it can't be connected directly to mains, it expects some lower ...
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2answers
134 views

Is a capacitive touch screen safe to use?

I was reading about capacitive touch screens. I understood that your hand picks some current flowing on screen. That sounds alarming. Is it safe to use a capacitive touch screen, since it picks small ...