Mild electric shock

[lnknprkfrevr]

Hi everyone !

I experienced mild electric shock when i touched the two hinges(that help the lid open and close) of my laptop.

Not only the hinges but also the vga port on the sides.

I'm from India and power source here is 220v~240v which is obviously converted to laptop voltage by the power adapter.

So i don't know where the problem lies . Is it in the laptop or the power mains of my room ??

Pls share your views

 

[gamblingman]

Usually shocks like that are from a static charge on your body and they discharge through a ground. In this case it was your computer!

If you are worried about the wiring being incorrect then you should be able to get a power outlet tester. Its a small, cheap device that plugs into the power outlet and has lights that indicate if the outlet is wired correctly. If you have the poles reversed, or the ground is not correct, or other, the lights on it will illuminate to show you what you need to fix.

Next time before you touch your computer, tap a grounded piece of metal. Sometimes I feel like I'm a walking capacitor, I get static shocks all the time.

And WOW, 220/240 for regular household outlets? Thats high. But I bet your toaster makes toast twice as fast as mine!!! ha ha

 

[strollin]

One of the reasons that laptops use a power adapter that converts from AC to DC before entering the laptop case is to prevent what you think is happening from ever happening. The AC voltage from your mains is completely isolated from the laptop within the power adapter. I agree that you probably got a static shock.

 

[Okedokey]

One of the reasons that laptops use a power adapter that converts from AC to DC before entering the laptop case is to prevent what you think is happening from ever happening. The AC voltage from your mains is completely isolated from the laptop within the power adapter. I agree that you probably got a static shock.

Thats nonsense. The reason why there is ac/dc conversion is because the electronics uses 12VDC.

 

[MMM]

One of the reasons that laptops use a power adapter that converts from AC to DC before entering the laptop case is to prevent what you think is happening from ever happening. The AC voltage from your mains is completely isolated from the laptop within the power adapter. I agree that you probably got a static shock.

If you care to understand PC power supplies your statement is flawed....have an understanding of the cheap ones and they can be lethal when electrical faults occur.
The modern PWM type PSU's are completely different to the old style transformer PSU's

As bigfella stated, AC to DC rectification required and to step the voltage from 220/240vac to 12vdc & othe low voltages as required.

In Inknprkfrevr case I would assume it is most likely a Static discharge as Laptops are prone to these situations at times.

 

[strollin]

Thats nonsense. The reason why there is ac/dc conversion is because the electronics uses 12VDC.

You really need to brush up on your reading comprehension skills. I said that the reason the conversion was done BEFORE entering the laptop case is to attempt to isolate the AC from the laptop. You also might notice that the power adapters are molded and sealed so they aren't able to be opened, another attempt to isolate the masses from ever coming in contact with the AC. Jeesh.

 

[Okedokey]

The conversion has nothing to do with safety pal.

Think of the many AC devices we use? Somehow you have connected safety to DC regulation. Not correct. Don't need to comprehend you any further.

 

[strollin]

The conversion has nothing to do with safety pal.

Think of the many AC devices we use? Somehow you have connected safety to DC regulation. Not correct. Don't need to comprehend you any further.

I agree that the conversion from AC to DC has nothing to do with safety and I never stated that, you somehow made that up in your head. I said the reason why the AC is kept OUTSIDE the laptop case is an attempt to isolate the user from the AC.

The conversion could just as easily be done within the case of the laptop but it isn't for a multitude of reasons. Keeping it outside the case keeps the weight and size of the laptop down AND makes things safer for the consumer.

 

[Okedokey]

Yeah, ok, you're not talking about safety, just isolating it from the user... and then go on to say "makes things safer for the consumer". Total nonsense. It has nothing to do with either. DC electronics is simply a different thing, components e.g. inductors, lc circruits etc, do different things. AC is not useful in electronics, never has been. Nothign to do with safety.

 

[MMM]

I said the reason why the AC is kept OUTSIDE the laptop case is an attempt to isolate the user from the AC.

It has nothing to do with keeping the user isolated from AC power
The external power supply was designed to recharge the laptop and not to be part of laptop to keep weight and size to a minimum only.

 

[strollin]

Yeah, ok, you're not talking about safety, just isolating it from the user... and then go on to say "makes things safer for the consumer". Total nonsense. It has nothing to do with either. DC electronics is simply a different thing, components e.g. inductors, lc circruits etc, do different things. AC is not useful in electronics, never has been. Nothign to do with safety.

I'm sorry, I apologize. It's obvious you know more about it than I do even though I completed my degree in electronics and started working in the tech field before you were born!

AC not useful in electronics, huh? Now you tell me? Damn, I wasted my time in electronics classes learning AC theory. Guess all the transmitters, receivers, power supplies, audio equipment, etc... that I worked on over the years only used DC.

You can naively believe that keeping fatal AC voltages as far away from the consumer as possible is not a design criteria if you like, I'll continue to believe differently.

 

[Symbol]

AC is not useful in electronics, never has been.

what? since when? stone age perhaps

 

[StrangleHold]

DC electronics is simply a different thing,

True. But the way you worded that sounds really weird. You do know the difference in AC and DC?

components e.g. inductors, lc circruits etc, do different things.

True. But what does that have to do with anything.

AC is not useful in electronics, never has been.

Now say what?

Dont really think the guys AC/DC converter has anything to do with him being shocked though.

 

[Okedokey]

I'm sorry, I apologize. It's obvious you know more about it than I do even though I completed my degree in electronics and started working in the tech field before you were born!

A laptop computer is a digital electronic circuit. AC and analogue circuits are not useful here. This has been the case since about the time i was born.

Im sure you're very experienced and have a shit tonne of stories, but I also have an electronic engineering degree (avionics) and to be honest if someone like you with a degree in such a field cannot see the difference between electrical and electronic principles Im stunned. I looked up valve technology in the 1960's and it came up with the same list you did:

Guess all the transmitters, receivers, power supplies, audio equipment, etc... that I worked on over the years only used DC.

Valves for example are an alternative to transistors (by the way valves sound great). They work by sufficiently heating up conductive mesh arrays causing electrons to 'jump' across the gap. In physics and in the real sense, the designer of this component undertood the beauty of what AC can do. BUT, thats not electronics thats applicable to a laptop. In the very said amp (e.g. 1974 Marshall JMP100 which I love), all the control gear (the electronics) for tone, graphic equalisation etc was on DC. Eiether way, electronics uses DC to reference the electron from a constant known. This is DCs major advantage.

Electronics operates on DC in almost every case for a good reason. Firstly DC provides a much better rail stability (ripple - required when your logic is based on 0.1 or 0.3V fluctuations) and in some electronic applications is essential for circuit operation (e.g integrated circuit logic and circuits that become reactive (when not desired) under AC conditions). You cannot do most things with AC in electronics without rectifiying. Basic fact. You certainly cannot operate logic transistor circuits such as a CPU. Of course power electronics can use AC, but thats for a specific reason. Almost every electronic application outside this very narrow band is in DC. On a side note, its also why power factor control is useless in a computer PSU as there is almost no reactive load.


This is why many applicances that use say motors (e.g. washing machines) use AC - however you will notice all of them have DC for the electronic PLL etc. They don't have the issue with safety do they? No, and neither would laptop - people work on their electric guitar amps all the time (im one of them). The reason for DC is because of basic physics. Safety is minor note.

This has got completely off topic however. Sorry to the OP, your mild electric shock was nothing more than static electricity. You'll be fine.

 

[strollin]

...
This is why many applicances that use say motors (e.g. washing machines) use AC - however you will notice all of them have DC for the electronic PLL etc. They don't have the issue with safety do they? ...

They don't have an issue with safety because they were designed with safety in mind. I don't understand why you can't see what I am talking about.

I'll repeat that I have never stated that the conversion from AC to DC is done for safety reasons, you somehow invented that yourself. I'm talking about WHERE the conversion is done. In a washing machine such as you mentioned above, the AC is isolated and grounded within the metal appliance shell in such a way so that the AC should never come in contact with the user. Typically, appliances have a sticker on them saying something along the lines of "Qualified Service Personnel Only" due to the presence of the potentially lethal AC. They are not designed to be opened by the average person.

Computers are different. The designers know that it's extremely likely that the typical user probably will open the case at some time. That's why computer power supplies (laptop and/or desktop) are designed in such a way as to minimize the potential of the user coming into contact with the very hazardous AC.

I'm simply saying that one reason (not the only or even the most significant reason) the conversion from AC to DC is done within the the molded "brick" power adapter of a laptop, not in the laptop case itself, is an attempt to make sure that the user never comes in contact with the AC. Many users, who are not really qualified to service electronic devices, will open their laptop or computer case for upgrades or whatever at some time.

You do agree that coming in contact with 120VAC (or 220VAC) is substantially more risky than coming in contact with 15-20VDC, don't you? I would go so far as to say that 120VAC is lethal whereas 15-20VDC is not.

BTW, thanks for the refresher on AC/DC electronics and valves (referred to as tubes on this side of the pond). Not sure why you feel the need to debate the usefulness of DC vs AC, they both have their applications.

I don't have any experience with Avionics but it seems to me that some components depend quite a bit on transmitting and receiving. They don't transmit in DC, do they?

 

[voyagerfan99]

In gonna close this thread before it gets out of hand. If OP still has concerns, he can start a new thread.


In my opinion it was just static electricity that had built up and been released when OP touched the hinges on his laptop.