*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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3answers
110 views

Safety of this circuit (involving hand-to-hand current):

Note1: The voltage source in diagram is 3 lantern cells in series. Note2: Hands are placed on acrylic/plastic mesh so not directly in contact with metal trays. The hands would be submerged for ...
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0answers
27 views

220v Grid Tie Inverter [migrated]

I just bought a 3000w 220v grid tie inverter and I'm wondering if it is safe to simply plug it into the 220v port in my laundry room (the one my dryer runs on) and then run it, or is there more I need ...
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0answers
53 views

Would electrified water hurt me? [duplicate]

Considering following scenario: What would happen, If electric plug went under water beeing powered, electrifiing water? I have two hypothesis, that I'm not going to test for obvious reasons :). ...
2
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3answers
120 views

Played with some lead solder without washing my hands for awhile, should I be concerned?

I was using some lead solder at work, and wasn't aware it was lead solder nor had anyone told me that it can be dangerous. For the most part I was just handling it. This was last week and I don't ...
1
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0answers
66 views

What regulatory and legislative requirements are important for avionics? [closed]

Lets say I was building a device that is designed to go into an international commercial airliner, e.g. a digital altimeter or a GPS device. What legislative and regulatory requirements, specific to ...
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0answers
69 views

PCB voltage and current

I am building new project, which I will power up the water tank heater from my smartphone. I have few safety though I want to ask here to get your opinion.. I am going to use AVR to run a relay, that ...
2
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2answers
139 views

Choosing the right Relay for the mission

I am building new project, which I will power up the water tank heater from my smartphone. I have few safety though I want to ask here to get your opinion.. I am going to use AVR to run a relay, that ...
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1answer
84 views

Choosing a transistor to Relay

I am building new project, which I will power up the water tank heater from my smartphone. I have few safety though I want to ask here to get your opinion. I am going to use AVR to run a relay, that ...
0
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1answer
41 views

Using Ground Off Another Circuit [closed]

I have a power outlet without a ground, but I have an electronic device which requires a real ground (can't use a GFCI protected outlet). Would it be okay to run an extension cable from an outlet ...
1
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1answer
59 views

Safety when working with CD burner laser

What kind of safety precautions should I take when working with a laser I've taken out of an old CD-RW burn drive? I'm making a small laser writer/printer to write on wood. Should I wear glasses? ...
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2answers
65 views

Safety concerns using metal switches near 300V (low current) lines?

I am building a nixie tube clock whose power supply in the best (or worst) case scenario will put out ~300V. This is obviously quite hazardous if not handled correctly. I need to use at least 1 spdt ...
3
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2answers
156 views

Explosion proof enclosure wiring

I am currently working on a device that is to be used in hostile environments. It needs to be explosion proof. Our team has decided to place our instrument in this housing shown here. ...
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2answers
73 views

Fault-current circuit breaker breaking on grounding neutral conductor?

I just put some lamps on and got the fault-current circuit breaker triggered. While skinning the earth conductor the knife touched the neutral. I was a bit puzzled: I thought that happens only under ...
0
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3answers
182 views

How did I survive a short hand-to-hand 230V shock? [closed]

About 5-10 years ago (can't remember when exactly), my father asked me to unplug a lawn mower from an ungrounded power outlet with no sunken part (the kind which had been outlawed by the EU for a few ...
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3answers
341 views

Giving shocks to students [closed]

My son's science teacher had 15 fifth grade students stand in a semicircle holding hands. The student at each end held an electrode connected to some kind of variable contoller. The teacher ...
1
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0answers
112 views

Would Beetee's electrocution plan work and kill the tributes in the lake? [closed]

I would like to understand the design of an electrical system to route the electricity from lightening into a salt water lake and to thus kill anyone in the lake. In its simplest form the design is a ...
0
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1answer
93 views

Safe to use 4.5v 300ma rated 'universal' ac/dc adapter with kids alarm clock that requires 5v 500ma? [duplicate]

Have a kids alarm clock that requires 5v 500ma for power supply option (but can also run on 3x AAA batteries). I have a universal adapter that can supply 4.5 or 6v (with the correct polarity) but it ...
1
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1answer
100 views

Safely discharging large value capacitor without blowing it up

This is related to my previous question. I have this circuit in which I discharge the capacitor by turning ON M2. The ON resistance of the MOSFET I have in mind (the picture shows the wrong MOSFET in ...
0
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0answers
25 views

What is the functions of Safety Interface Modules?

I read a manual of safety interface modules http://info.bannerengineering.com/xpedio/groups/public/documents/literature/62822.pdf I see "The Interface Module offers a series connection of normally ...
1
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1answer
144 views

How to safely use the power-socket ground for the anti static wrist strap?

I saw as practice to use the power-socket ground for the anti static wrist strap, I saw this done where there is no available specially designed ground for anti-static pads and bracelets, but this may ...
2
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0answers
82 views

Options for a simple over-temperature cut-off?

I am designing a heater circuit that will be used in a product to be produced in small to medium quantities (hundreds to thousands of units, not tens of thousands). This heater will be PWM controlled ...
2
votes
1answer
83 views

Wearing “conductive shoes” instead of heel grounders?

I've been looking into alternatives to heel grounders since they're kind of cumbersome to put on and take off often (not to mention being uncomfortable) and I'm considering buying a pair of ...
0
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0answers
40 views

ATX power supply repair intermediate power up testing

Hi I'm repairing ATX power supplies these days. I'm so newbie to the repairing business and I wants read some value of some test points when the device is active. How could I do this? Is it oky to do ...
2
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2answers
132 views

Are touch lamps safe?

I've used "touch lamps", where you turn it on and off by touching the lamp. As I understand it, this works by putting a small electrical voltage through the human body: touching the lamp completes ...
4
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1answer
143 views

Health considerations when disassembling consumer electronics

I'm doing some simple diy projects with my Arduino board so I buy various electronic parts (pretty much all the basics like resistors, capacitors, etc..) to experiment and see how things work. ...
6
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2answers
309 views

LED driver safety

I plan using a AC to DC converted with constant current output (LED driver AUBIG A8HH20317) in order to light high-power LEDs (about 12*3W LEDs). The more LEDs, the higher voltage at the output, but ...
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3answers
250 views

Are modern processors safe from backdoor? [closed]

I have been reading so many thing about leaks of surveillance recently, Most of the things covered under NSA 2013 Mass surveillance disclosure I use the chips of Microchip for designing few ...
1
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3answers
101 views

Is it safe to have 4V continuously supplied to a lithium battery?

I have a compact digital photo camera that will be on for very long periods(for a time-lapse video). It is powered by a Lithium-Ion 3,7V, 720mAh battery I want to supply 4V to the battery terminals, ...
5
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4answers
154 views

Safe Discharge Rate of Alkaline Batteries

I am working on a portable project. I need to pull 3,500mA average with 10,500mA peak at 3.6v-4.5v. I see that "D" Alkaline Batteries are rated for 1.2-1.5v and 12,000mAh. So I am looking at using a 3 ...
12
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2answers
823 views

Is it OK to solder a power cord?

A few people have advised me to never solder a power cord directly to a PCB, but they couldn't explain why not. Why can/can't I solder it directly?
3
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0answers
106 views

How to save electronic equipment from ants? [closed]

Today I brought out my external HDD and it was full of red ants. It took me an hour to remove the ants (it seems quite impossible to remove all of them; some are still inside). I always see some ants ...
3
votes
1answer
274 views

Charging batteries - what should I know

So I want to learn about batteries and the process of charging them. As a project, I'm going to create a solar powered charger to charge a 9v NiMh battery with 175mah capacity. I have a 15v solar ...
2
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3answers
259 views

Identifying potentially dangerous capacitors

I'm looking for guidelines on how to identify capacitors which have the potential to cause pain, injury or death due to electrical shock if not handled correctly. I recently purchased a "getting ...
0
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1answer
197 views

Does a power supply GND connection need a resistor?

I am creating a power supply for my work station, and I have a input of 13.5 - 19V DC from a converter on POWER_JACK. From this input voltage I want to derive 12V, ...
5
votes
4answers
299 views

Is it dangerous if I do not connect the ATX shield to ground?

I'm living in an Asian country and there isn't a ground connection provided on sockets here. There is only L (live) and N (neutral) so I need to use a 3-to-2 converter. It means that the ATX case does ...
1
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2answers
291 views

Advice on safe discharge circuit for HV Capacitors (400v)

In designing a relatively high voltage DC-DC converter, my output capacitor happens to be a 100uF electrolytic charged to 400v nominal. Efficiency is a design constraint, so I would like to know of ...
3
votes
3answers
286 views

How does power in “wall wart” power supplies work?

I'm new to electronics and am having trouble understanding how power supplies convert 120AC into a safe, manageable DC voltage. So far, I understand that there's a transformer to step the voltage ...
6
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5answers
919 views

Is soldering wires directly on a NiMh battery safe?

I'd like to know if soldering two wires directly on a NiMh battery is considered as safe or not. My fear is that battery would explode (right in my face) because ...
3
votes
1answer
182 views

What frequency and voltage should the electrical outlet have in order to be the least harmful to humans and still be useful to modern appliances?

Studying electronics a few years back I came across a graph like this one: Showing that 50-60Hz current that is by far the most popular power coming from the electrical outlets in homes everywhere ...
1
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1answer
273 views

Grounding in a DC circuit on a vehicle

I am working on a vehicle with batteries, but i am not quite sure if my grounding solution/design is correct. It is supplied with two 12VDC batteries in series, connected to a DC-DC (24VDC-24VDC) ...
0
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2answers
84 views

How to isolate a soil moisture sensor

When using a soil moisture sensor in a plant to measure water indoor, how can we avoid dangerous water and electrical interaction. In general, when there's water in the plant When watering the ...
0
votes
3answers
141 views

Does a ground fault compromise the whole circuit?

(this image taken from http://www.allaboutcircuits.com/vol_1/chpt_3/3.html) Based on this picture, would a tree across the bottom wire of the circuit (the solid wire, not the dashed wire ...
2
votes
3answers
171 views

Cheap ESD/safety Mat

I need to get some sort of ESD/safety mat (2 actually) for working at home to protect myself and equipment. I was wondering what to look for/avoid if I were to purchase a rubber mat from a rubber ...
-3
votes
1answer
218 views

I want to build a portable railgun and I'm a complete rookie [closed]

I'd like to enter the world of electronic hobbies by making a railgun, and so far I know that I understand the basics of the device and that I need high amounts of direct current. However, I am ...
3
votes
3answers
2k views

How can I safely power two 3v motors from a 9v battery?

I'm making a Sumo Bot from scratch and I had purchased two 1.5-3v DC motors from Radio Shack to run with my Arduino Uno v3. I'm using a 9v battery to power my Arduino alongside an RF receiver, Quad ...
1
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1answer
123 views

Live-Neutral transformer fault

In this critique of an ELV PSU design, it is suggested that a "Live-Neutral" fault could result in a fault current of thousands of amps. I'm sceptical. Please could someone explain how this could be? ...
3
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1answer
88 views

Possible measures to make power supplies safe

I'm looking for a list of ways that mains-powered ELV power supplies with touchable terminals can be made safe in the case of transformer failure with primary and secondary coils becoming connected ...
6
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4answers
920 views

Detect “real” overcurrent/short-circuits vs. current peaks

We have a MOSFET that drives a load. The load has a sense resistor in its current path and its voltage is used to trigger a circuit that can disconnect the load if we detect an over current ...
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1answer
126 views

Why UPS for sensitive SMD development?

My friend suggests me UPS for SMD development. I already have a a surge protector over all devices. He recommended the UPS that transmit all energy through its battery and he recommend to find some ...
4
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1answer
305 views

Disposal of the used acid/hydrogen peroxide etchant?

This thread repeated the question how to dispose the used acid/hydgogen peroxide etchant. So how can I dispose acid/hydrogen peroxide etchant? Perhaps interesting thread to other readers, Disposal of ...