I have a problem in my sound light device:

[Rami00972]

I make it before week and its working very will in my computer speaker line ,but when I connect it to my friend computer it make a short and cut the power , I thing that I need to make a buffer stage but not as the same one as we know cos It’s a wav signal from the speakers connector-
Pleas help me.
this is the schematic of themmodel

 

[RadioRon]

Your circuit has no isolation between one side of the 220V mains and the computer chassis ground used as the reference for your input signal. In this situation, whether you suffer a ground fault or not depends on which way each piece of equipment is connected to the mains, that is, which way the plug is inserted into the mains outlet. This situation is not safe and you should alter your circuit for improved safety. I recommend that you either use an isolation transformer on the mains side of your lamp circuit, or you alter the circuit so that there is no ground connnection between input and output. This might be done using an optoisolator.

 

[Hero999]

Well I've never seen a mains plug that can be pluged in more than one way.

Either way, this is a bad idea, even if the neutral is connected to the low side, it will create a nasty earth loop that can cause you all sorts of problems.

 

[Nigel Goodwin]

Well I've never seen a mains plug that can be pluged in more than one way.

That's because you live in the UK in the 21st Century - many countries don't have plugs that only fit one way!. Even the UK didn't 40-50 years ago!.

You're showing your youth!

 

[Rami00972]

You mean to use 1:1 220v transformer but is there any other specification for it.
like this in radio shake
**broken link removed**

 

[ericgibbs]

You mean to use 1:1 220v transformer but is there any other specification for it.
like this in radio shake
**broken link removed**

hi,

That transfomer is not suitable.

Look at this link:**broken link removed**

The MOC3041 opto would be an ideal component for driving the triac's

Eric

 

[Rami00972]

hi,

That transfomer is not suitable.
...................
The MOC3041 opto would be an ideal component for driving the triac's

Eric

I thing its the same problem cos in the final i should but all the Grand tracks together "for the opto and the triac see the schem. if it the same as you mention to drive the triac??. i don't have problem to drive it, its not damaging the ic.
So i have the same prob. if its True or not
thanks

 

[RadioRon]

ericgibbs is correct that this example of isolation transformer from RS is not suitable. This example is a low power signal transformer for audio isolation. You need a power transformer specified for use on 50Hz mains. The most important specification will be how many Watts (or VA) it is designed to pass, and in your case the number of watts (or VA) must be equal to or greater than the number of watts of your lamps.

The smarter solution is to alter your circuit to isolate the input and output, since an isolation transformer is large, heavy, and expensive while an optoisolator included in the design is small, cheap and efficient. But it has to be done carefully and correctly.

 

[ericgibbs]

I thing its the same problem cos in the final i should but all the Grand tracks together "for the opto and the triac see the schem. if it the same as you mention to drive the triac??. i don't have problem to drive it, its not damaging the ic.
So i have the same prob. if its True or not
thanks

hi,
Your latest circuit is not correct.
Did you look thru the datasheet for the opto isolator I posted, check the applications section on the datasheet.

If you need more help, let us know.

Eric

 

[ericgibbs]

hi,
Look at this drawing.

 

[Rami00972]

i will try it

 

[ericgibbs]

i will try it

hi,
Calculate R1 [ opto diode driver] to suit the +5V logic voltage, a value of about 220/270hm: should be OK.

NOTE:
There is NO ground/0v connection between the 0V of the opa/logic and the
mains wiring.

Eric

 

[Rami00972]

thanks for all i test it and its working very well