On 6/30/2012 3:58 AM, u...@downunder.com wrote:
> On Fri, 29 Jun 2012 04:32:57 -0700 (PDT), Srinivas Nayak
> <s...@gmail.com> wrote:
>
>> Hi,
>>
>> I am designing a 8051 microcontroller system. It has ports for interfacing.
>> How can I control a 230V 100W Electric Bulb using 8051 microcontroller ports?
>>
>> In essence, how do we control high voltage applications using 8051 microcontroller?
>
> In the USA low voltage is anything below 600 V, in the rest of the
> world (IEC) low voltage is something below 1000 Vac or 1500 Vdc.

http://en.wikipedia.org/wiki/IEC_60038

>
> In reality, you have two options:
>
> * run the 8051 and associated peripherals, such as switches and
> potentiometers close to ground potential and use some means, such as a
> relay or optoisolator to drive a TRIAC at mains voltage.
>
> * Let the 8051 float with the mains voltage close to the TRIAC gate
> potential, but please remember, any interfaces, such as switches and
> potentiometer shafts must be certified for at least 2500 V isolation
> voltage, depending on national standards.
>

On Sat, 30 Jun 2012 14:04:46 +0800, "Bruce Varley" <b...@NoSpam.com>
wrote:

>
>"George Neuner" <g...@comcast.net> wrote in message 
>news:h...@4ax.com...
>>
>> I am always amused to see "High Voltage" warning signs on electrical
>> equipment because high voltage isn't necessarily dangerous.
>
>That's just being picky. The aim of high voltage signs is to keep people 
>away from things that can harm them. 

Better just to say "electrocution danger", which is correct without
being misleading.

I *am* being picky, but I don't appreciate the continual dumbing of
society.  The majority of people already are uninformed/misinformed
enough as it is without deliberate misinformation being spread - even
with good intentions - by those who know better.

George

hamilton wrote:

> On 6/30/2012 3:58 AM, u...@downunder.com wrote:
>> On Fri, 29 Jun 2012 04:32:57 -0700 (PDT), Srinivas Nayak
>> <s...@gmail.com> wrote:
>>
>>> Hi,
>>>
>>> I am designing a 8051 microcontroller system. It has ports for
>>> interfacing. How can I control a 230V 100W Electric Bulb using 8051
>>> microcontroller ports?
>>>
>>> In essence, how do we control high voltage applications using 8051
>>> microcontroller?
>>
>> In the USA low voltage is anything below 600 V, in the rest of the
>> world (IEC) low voltage is something below 1000 Vac or 1500 Vdc.
> 
> http://en.wikipedia.org/wiki/IEC_60038
> 
>>
>> In reality, you have two options:
>>
>> * run the 8051 and associated peripherals, such as switches and
>> potentiometers close to ground potential and use some means, such as a
>> relay or optoisolator to drive a TRIAC at mains voltage.
>>
>> * Let the 8051 float with the mains voltage close to the TRIAC gate
>> potential, but please remember, any interfaces, such as switches and
>> potentiometer shafts must be certified for at least 2500 V isolation
>> voltage, depending on national standards.

What the OP didn't specify, and what everyone else so far has failed to ask, 
is what sort of control does he want over this 100W lamp. Is it simple 
on/off control or does he require an element of dimming?

The dimming control requires a little more effort to properly synchronise 
the pulse control of the Triac. Then there is filtering to consider.

-- 
********************************************************************
Paul E. Bennett...............<email://P...@topmail.co.uk>
Forth based HIDECS Consultancy
Mob: +44 (0)7811-639972
Tel: +44 (0)1235-510979
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"George Neuner" <g...@comcast.net> wrote in message 
news:h...@4ax.com...
> On Fri, 29 Jun 2012 21:11:56 +0200, Hans-Bernhard Bröker
> <H...@t-online.de> wrote:
>
>>On 29.06.2012 13:32, Srinivas Nayak wrote:
>>
>>> How can I control a 230V 100W Electric Bulb using 8051 microcontroller 
>>> ports?
>>
>>If you need to ask, the answer has to be yelled:
>>
>> YOU CAN'T, AND YOU'RE NOT EVEN ALLOWED TO TRY.
>>
>>Seriously.  That's a potentially lethal voltage you're talking about.
>>As in: get this wrong and odds are you'll KILL someone.  So don't go 
>>there.
>
> Lethal *power* anyway 8-)
>
> I am always amused to see "High Voltage" warning signs on electrical
> equipment because high voltage isn't necessarily dangerous.  With
> enough amperage any voltage can kill, but it's well know to police and
> security forces that the tiny 50KV stun guns (don't know the amps) are
> fairly useless ... they can startle a person and maybe hurt them but
> they are very unlikely to incapacitate - the professional ones now are
> 1-2MV.
>
> George


But by your argument, you should be looking at Joules not Volts. 

Op Mon, 02 Jul 2012 14:26:23 +0200 schreef Bill Davy  
<B...@synectixltd.com>:
> "George Neuner" <g...@comcast.net> wrote in message
> news:h...@4ax.com...
>> On Fri, 29 Jun 2012 21:11:56 +0200, Hans-Bernhard Bröker
>> <H...@t-online.de> wrote:
>>
>>> On 29.06.2012 13:32, Srinivas Nayak wrote:
>>>
>>>> How can I control a 230V 100W Electric Bulb using 8051 microcontroller
>>>> ports?
>>>
>>> If you need to ask, the answer has to be yelled:
>>>
>>> YOU CAN'T, AND YOU'RE NOT EVEN ALLOWED TO TRY.
>>>
>>> Seriously.  That's a potentially lethal voltage you're talking about.
>>> As in: get this wrong and odds are you'll KILL someone.  So don't go
>>> there.
>>
>> Lethal *power* anyway 8-)
>>
>> I am always amused to see "High Voltage" warning signs on electrical
>> equipment because high voltage isn't necessarily dangerous.  With
>> enough amperage any voltage can kill, but it's well know to police and
>> security forces that the tiny 50KV stun guns (don't know the amps) are
>> fairly useless ... they can startle a person and maybe hurt them but
>> they are very unlikely to incapacitate - the professional ones now are
>> 1-2MV.
>
> But by your argument, you should be looking at Joules not Volts.

It's a bit more complicated than that.

http://en.wikipedia.org/wiki/Electric_shock


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On 29.06.2012 23:20, George Neuner wrote:
> On Fri, 29 Jun 2012 21:11:56 +0200, Hans-Bernhard Bröker
> <H...@t-online.de> wrote:

> I am always amused to see "High Voltage" warning signs on electrical
> equipment because high voltage isn't necessarily dangerous.

Right --- but the catch is that high voltage is quite necessary to be 
dangerous.  I.e. first the voltage has to be high enough, and only 
_then_ there needs to be enough current available at that voltage to 
cause severe harm.

> With enough amperage any voltage can kill,

You try killing someone with 10000 A at 1 mV.  Good luck.

On 30.06.2012 19:05, George Neuner wrote:

> I *am* being picky, but I don't appreciate the continual dumbing of
> society.  The majority of people already are uninformed/misinformed
> enough as it is without deliberate misinformation being spread - even
> with good intentions - by those who know better.

Well, if _that's_ the kind of fight you want to pick, I hereby anoint 
you EWHWCEPDPBGIkW/h  (Engineers of the World's Holy Warrior in Charge 
of Eradicating the Plague that is: Devices' Power Being Given In kW/h.). 
  After all, it's better to pick a fight that there's still a chance you 
might win.

;-)

>Hi,
>
>I am designing a 8051 microcontroller system. It has ports for
interfacing.
>How can I control a 230V 100W Electric Bulb using 8051 microcontroller
ports?
>
>In essence, how do we control high voltage applications using 8051
microcontroller?
>
>Sincerely,
>Srinivas Nayak
>

http://www.futurlec.com/Opto_Relay_4.shtml or similar ... and be careful.

	   
					
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