Poly Variable Condenser (Pinout Question)

Discussion in 'General Electronics Chat' started by johncena, Aug 14, 2011.

  1. johncena

    johncena Thread Starter Member

    Joined:
    Aug 15, 2010
    Messages:
    32
    How do you connect the Poly Variable Condenser ( it has 3 pins) to the TDA7000 FM Receiver which only requires 2 pin for the Resonator part of the circuit.

    i need that 2-60pF range of the PVC and i want to know what will i use between those 3 pins.

    The technical spec is here --> http://mzentertainment.com/technical_archive/TTWM_variable_capacitor.gif

    and here's the spec:

    TTWM Poly Variable Condenser / Capacitor.
    Two section, apx 60pF and 140pF max.
    Commonly used in portable transistor AM/FM radios.


    Here's the pic:

    http://mzentertainment.com/store_pp_images/dzw_store_varicap_TTWM_60_160pf_000140_zoom.jpg

    I would like to post the schematic, but unfortunately, the website was down at the moment.

    But getting that 2-60pf in series with 56pf and parallel with 33pF and 56nH inductor will provide a 85Mhz to 113Mhz
  2. Kermit2

    Kermit2 Well-Known Member

    Joined:
    Feb 5, 2010
    Messages:
    2,434
    The center pin is common to both and without a clear indication on the datasheet, I would GUESS the Osc section would be the left side and the Ant section the right side when viewed from above with the pins toward you. If not then its the other way around :)

    You just need to make connection with two pins. you can bend the other one up and allow the other two to go into the board. Be gentle. You may have to unbend it and bend the other side up if you get the wrong side.
    johncena likes this.
  3. johncena

    johncena Thread Starter Member

    Joined:
    Aug 15, 2010
    Messages:
    32

    Thanks!, now i'm sure that Osc is in Leftside and Ant in the right side..
    I just noticed it in the picture (the last part) there is a "O" and "A" lettering...
    Thanks for the clarification on the pin parts.
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