Help needed pn creating class ab amplifier

Discussion in 'Homework Help' started by balabalabala, Nov 22, 2009.

  1. balabalabala

    Thread Starter New Member

    Nov 22, 2009
    1
    0
    Can anyone pls explain about how to design this circuit..
    ===========================================

    You must design and build an amplifier with the following characteristics:
    1) At least 0.5W output power when used with a 4Ω load, vi = 200mVpk
    @100Hz
    2) DC power supply of +/- 5V or less
    3) Minimize distortion
    You must also desig an amplifier with the following characteristics:
    1) At least 0.5W output power when used with a 4Ω load, vi = 10mVpk
    @100Hz
    2) DC power supply of +/- 5V or less
    3) Minimize distortion
    You must use the parts you are given. If you feel your design would benefit from
    additional resistors, you may use them once you have justified your request to the
    course instructor. Your justification must include a design that uses only the given
    components, along with the improved design that uses the values you are
    requesting; you must be able to fully explain both designs.
    Along with your components, you will be provided one breadboard per group.
    Please return both, the component package, and breadboard, at the end of the
    course. You will have to provide the connecting wires you need and power supply
    and/or batteries.
    You must supply a Multisim / OrCad simulation, input output transfer function
    showing the frequency dependency, bandwidth and gain, and 3dB frequencies.
    You must also supply the hand calculations showing the DC current and voltage
    values and relevant impedances (including the input and output resistances).

    List of components, i have
    ======================
    Class AB/B 1/2W, Class A 1/4W BJT Amplifier Kit
    200mVpk @100Hz, 4ohm load (8ohm speaker)

    Sayal Part Number Description No needed

    MJE210-1 MJE 210 PNP 5A BJT 1
    MJE182-1 MJE182 NPN 3A BJT 1
    HEJH-1933-4 heatsink 2
    MPS6521-5 MPS6521 NPN 100mA BJT 1
    MPS3638-5 MPS3638A PNP 300mA BJT 5
    1N914B-10 silicon diodes, 300mA 2
    CER-255-5 electrolytic cap, 100uF, 16V 2
    CETH-4744A-1 bipolar cap, 47uF, 50V 2
    CTR-2577-1 cap tantalum 33uF, 20V 1
    RAB-194-10 6k2 resistor, 1/4W 1
    RAB-213-10 39k resitor, 1/4W 5
    RAB-470R-100 470ohm resitor, 1/4W 1
    ? 1k resitor, 1/4W 6
    ? 2k2 potentiometer, screwdriver adjustable, value not critical 1
    ? 8ohm speaker, 1W 1
    ? 741 opamp 1
    ? 19k 1
    ? 4M 1
    ? 200k 1
    ? 10k 1
    ? 0.1uF, 30V 1
    ? 0.01uF, 30V 1


    Thanks in advance
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    This certainly sounds like a homework problem assigned by an instructor/teacher/professor.

    It really belongs in the Homework Help forum.

    Post your schematic as it is currently.

    Your teacher/professor/instructor must have already covered the elements of amplifier construction, or you would not have received this assignment.

    You must have some idea of how to begin, or else you have been sleeping in class and neglecting your homework.

    We cannot do it for you. However, if you show what work you have accomplished so far and are truly "stuck", we can help you.

    If you don't even know where to start, then you will be re-taking the class/course next semester.
     
  3. blueroomelectronics

    AAC Fanatic!

    Jul 22, 2007
    1,758
    98
    Can't imagine why they'd use the ancient 741 considering Sayal is in Ontario Canada. We do have modern parts up here eh.
     
  4. studiot

    AAC Fanatic!

    Nov 9, 2007
    5,005
    513
    Since the required frequency of operation is 100Hz a 741 is entirely appropriate.

    Hint to the OP the 741 is unecessary for part 1. Why would you use it in part 2?
     
  5. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    He said he has two amplifier kits and listed the parts in them.
    Why doesn't he just build the kits?
     
  6. blueroomelectronics

    AAC Fanatic!

    Jul 22, 2007
    1,758
    98
    Maybe the instructor took away the PCB & Schematic. Easy way to make a quiz actually.
     
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