Selecting Power supply

Discussion in 'General Electronics Chat' started by lubnaan90, Feb 26, 2010.

  1. lubnaan90

    Thread Starter Active Member

    Jan 13, 2010
    196
    2
    Hello to all,

    Having trouble selecting the right power supply for the circuit in the attachment.

    The attachment has two circuits , both of them belong to one project (audio spectrum Grafix)

    Circuit (1) on the upper page is "Filter & switching" & the lower one is "Oscillator ,counter& decoder,VUled:

    Both the Circuits are connected (control connection on both the circuits)

    It would be very nice if any one can advise me , What kind of Power supply should i use for Circuit "1" ?
    Do i use a separate Power supply for Circuit "2" ?

    REGARDS,
    LUBNAAN
     
    • hhhh.jpg
      hhhh.jpg
      File size:
      276.2 KB
      Views:
      51
  2. bertus

    Administrator

    Apr 5, 2008
    15,652
    2,348
    Hello,

    Is there no info on the site you found the schematics?

    It looks like the "analog" schematic uses a dual powersupply for the opamps.
    The "digital control" schematic uses a single powersupply +VCC.

    The values of the voltages are not given.

    Greetings,
    Bertus
     
    lubnaan90 likes this.
  3. lubnaan90

    Thread Starter Active Member

    Jan 13, 2010
    196
    2
    Following are the information i collected from the PDF Databook i found with the schematics.

    OP AMPs in this circuit use dual power supply. Because we need 10 filters
    so we use 2 ICs with 4 OP AMPs inside and 1 IC with 2 OP AMPs. ICs used
    are TL084 (4 OP-AMPs) and TL082 (2 OP-AMPs).
    The following is specification of two ICs:
    - Working voltage: ±3 ¸ ±18V.
    - Offset voltage Vos(max): 15mV.
    - Input bias IB(max): 400pA.
    - Bandwith: 3MHz.
    - Maximum input voltage: ±30V.
    - Increasing voltage speed: 13V/ms.
    - Input resistance: >1012W.
    - Consumption current(max): 5,6mA for TL082 and 11,2mA for
    TL084.
    Specification at condition of Vcc = ±15V, temperature T = 25oC.
     
  4. bertus

    Administrator

    Apr 5, 2008
    15,652
    2,348
    Hello,

    I know the specs of the TL08X.
    The 4017 and the 4069 will work from 5 to 15 volts.
    The LM3914 will work from 9 to 25 volts.

    I would take ± 12 Volts for the "analog" schematic and + 12 Volts for the "digital" part.

    Is there no info given on the site where you got the schematics?

    Greetings,
    Bertus
     
  5. lubnaan90

    Thread Starter Active Member

    Jan 13, 2010
    196
    2
    To be honest , i was sent a PDF file from an old friend , it was especially meant for building of Audio spectrum Analyzer project , There is no such site where i found the schematic .
    The schematic are all from the PDF sheet itself.

    Regards
     
  6. lubnaan90

    Thread Starter Active Member

    Jan 13, 2010
    196
    2
    Which of the following Transformers is recommended for the Analog schamatic ?

    1) 0,5W 2x9V/28 mA
    2)
    1,5W 2x9V/85mA
    3)
    1,5W 2x12V/63mA
    4) 2
    ,5W 2x9V/140mA
    5) 2,5W 2x12V/105mA
    6) 4
    W 2x12V/170mA
    7) 6W 2x6V/500mA
    8) 6W 2x9V/330mA
    9) 6W 2x9V/330mA

    Before recommending the transformer, Please consider that , I will have to build a Rectifier circuit aswell & the capacitor will pump up the voltage .
     
  7. bertus

    Administrator

    Apr 5, 2008
    15,652
    2,348
    Hello,

    You could try something like this using transformer 6:

    [​IMG]

    Greetings,
    Bertus
     
  8. lubnaan90

    Thread Starter Active Member

    Jan 13, 2010
    196
    2
    Thank you for your reply Bertus
    OK, will proceed with your instructions.
    I have attached a picture of my project , the Hardware is almost complete,
    The big Circuit is ANALOG & the Smaller one is DIGITAL .
    I'll be glad to receive Comments or advises if any.
     
  9. bertus

    Administrator

    Apr 5, 2008
    15,652
    2,348
    Hello,

    What powersupply are you going to use for the display / control part?
    I think this needs to be more than 0.5 A (when all leds in one row are lighting) at the 12 Volts mentioned.

    Greetings,
    Bertus
     
  10. lubnaan90

    Thread Starter Active Member

    Jan 13, 2010
    196
    2
    I was planning to use 12volt , 500mA Wall DC power supply.
     
  11. bertus

    Administrator

    Apr 5, 2008
    15,652
    2,348
    Hello,

    Is the wall DC powersupply a stabelized one?

    Greetings,
    Bertus
     
  12. lubnaan90

    Thread Starter Active Member

    Jan 13, 2010
    196
    2
    Its just a Simple DC wall adapter that came along with my Panasonic Home Cordless Telephone.
    I don't know if its Stabilized or no .

    It has an output of 12V / 500mA
     
  13. bertus

    Administrator

    Apr 5, 2008
    15,652
    2,348
    Hello,

    You could try.
    Put the ground connections of both boards together.
    This way you will not have a "floating" ground.

    Bertus
     
  14. lubnaan90

    Thread Starter Active Member

    Jan 13, 2010
    196
    2
    Thankyou,
    Got your point .
    Will keep Updated.
     
  15. lubnaan90

    Thread Starter Active Member

    Jan 13, 2010
    196
    2
    Hello

    Just found a dual output Transformer in my Storeroom with the following parameters ,

    Output Voltage : 2 x 12 Volt
    Output Ampere : 3 Amps
    Output Power 45 : watts

    Is it appropriate to use the above Transformer for the analog circuit .
     
  16. bertus

    Administrator

    Apr 5, 2008
    15,652
    2,348
    Hello,

    That is perhaps a bit overdone for the analog part.
    There are only a couple of filters on that board.

    Greetings,
    Bertus
     
  17. lubnaan90

    Thread Starter Active Member

    Jan 13, 2010
    196
    2
    As a matter of fact, new Transformers over here in my City are very Expensive & I was trying to avoid spending extra buck by buying a new transformer for the analog circuit , So found this one , but it seems its too powerful & can be a risk factor .
     
  18. bertus

    Administrator

    Apr 5, 2008
    15,652
    2,348
    Hello,

    You can use it.
    The 7812 and 7912 will reduce the current to the board to about 1.5 A.
    Do you have the datasheets of the stabelizers?
    The transformer is powerfull enough to power both boards.
    If you want to have a seperate power for the controller board you can use a second 7812 for it.

    Greetings,
    Bertus
     
    Last edited: Feb 27, 2010
  19. lubnaan90

    Thread Starter Active Member

    Jan 13, 2010
    196
    2
    Hello,
    Thank you for your reply & the Data-sheets.
    I will go ahead & follow the instructions you posted & will keep you updated.
     
  20. lubnaan90

    Thread Starter Active Member

    Jan 13, 2010
    196
    2
    Hello,

    What is the use of 1N4001 Diode connected to the input & the output of both the IC,s & also the diodes which is grounding the Outputs , are those diodes necessary to be present on the circuit ?
    [​IMG]
    Is it ok to use the circuit i have attached ?
     
    Last edited: Feb 28, 2010
Loading...