Noise pick up and controller

[karthickb3e]

hi,
for our project msp430g2211 controller is used.. in that noise is picked up in input to the comparator... for that we used capacitor across the controller port pin with respect to ground... noise is arrested.....

but putting of capacitor to the port pin takes high current at initial state.. is it really?

then how to arrest noise ..,please give solution......

and also i have one more doubt.. noise is highly pick-up in the our transistor amplifier stage ... what are the remedies to take care to prevent the noise....

 

[goldsmith]

Hello Dear B.Karthick
You can use a faraday cage . or you can use a polygon on your circuit board.
Good luck
Goldsmith

 

[karthickb3e]

thank you goldsmith ...
u mean copper pouring ah.. i am already tried... but not solved..
Faraday cage ( i searched this in net) and bring metal near to amplifier circuit.. the noise gets reduced.. but the metal is connected to ground the noise level is similar.. what to do in this case....

and the real Faraday cage is home much cost .. and where it is available....

 

[goldsmith]

Again Hello my friend
You can make a simple faraday cage with yourself . ( it is the solution of many of my circuit noise rejection !). and at first step , tell me , that , can you measure the value or frequency of noise ?
and in the other hand , there is many way to noise rejection , if you want that i help you at better way , you should tell me more explanation , about the are of circuit ( for example is the place of circuit the places such as factories what will made bad noises ?!) and about power supply of your circuit . it is impossible that noises can go inside the faraday cage . as i understood , the noises are permeable on your supply and thus they are inside the cage ! so the power supply quality is very important.
Good luck
Goldsmith

 

[karthickb3e]

thank you my friend Mr.goldsmith ...
i attached my power supply circuit .. please suggest any problem in it?

where Vs is 30V....

 

[goldsmith]

Again Hi
Ok
No problem with that . but i want to talk about one of my experiences : when i wanted to build an oscillator with 500KHZ frequency some month ago , do you know , that what i saw ? a magic behavior ! it didn't oscillate ! simply ! but do you know what did i do to improve it ? iused a capacitor with 10uf value , near of my oscillator supply . ( my power supply had 4700uf capacitor at it's out put ) . but when i used that simple capacitor nearby my transistor , it oscillated as well as !!!!! the equivalent circuit of wire , was the cause of that event ! i didn't say this things for fun! my mean is that at that low frequency it was big problem ! so when you want work with logic circuits , or Miro controllers , what have oscillator internally , ( such as 16MHZ with crystal ) you should put a capacitor at nearest way with their supply pins !

And about polygon : you can use polygon with ground as well as . it will help to the behavior of your circuit .
And about latest thing that you said :
What is your mean by : "where VS is 30 volt " ?????!!!!!!!
By the way , i forgot to say it , that do you want the reason of the effect of that capacitor ? it is possible that you think , that it is just a simple DC voltage , but not infact ! the current has high frequency components when you need it as an oscillator , thus the wire will try to reduce this components !

Good luck
Goldsmith

 

[karthickb3e]

What is your mean by : "where VS is 30 volt " ?????!!!!!!!

Vs is my input regulated DC voltage - +30 Volts

 

[goldsmith]

Is your mean by -+30 that your input is simultaneous ?

 

[karthickb3e]

sorry my mistaken in putting hypen.(-)....


my input is +30V dc supply

 

[goldsmith]

if your out put is 3.3 volt and your input is 30 volt and your regulator is linear , i think if you get current from that , your regulator will convert to the hell !!!!! ( thus the temperature noise will increase )
Respect
Goldsmith

 

[karthickb3e]

that is our specification ... that the input is 5 to 30V