FM Tracking Transmitter resistor help

Discussion in 'The Projects Forum' started by markosillypig, Feb 4, 2013.

  1. markosillypig

    Thread Starter Active Member

    Jul 21, 2008
    184
    0
    hi all
    i'm making an fm tracking transmitter but i'm having trouble getting hold of sensibly priced 4m3 resistors
    so i was wondering if it has to be a 4m3 or could i use a
    4m7 instead if its no good i will get a 3m3 and 1 meg in series
    here is the schematic and component list

    cheers
    marko

    Resistors:
    1) 4.3 Meg Ohm
    1) 1 Meg Ohm
    1) 100 Kilo Ohm
    1) 10 Kilo Ohm
    1) 220 Ohm




    Capacitors:
    1) .1 uF
    3) .01 uF
    1) 5 pF
    1) 22 pF
    1) 6 to 50 pF Adjustable


    1) 4011 Quad NAND gate
    1) 2N2222 transistor
     
  2. MrChips

    Moderator

    Oct 2, 2009
    12,442
    3,361
    What is the purpose of the 4.3MΩ resistor?
    Any thing from 1MΩ to 4.7MΩ should work.
    Or put two 2.2MΩ in series.
     
  3. crutschow

    Expert

    Mar 14, 2008
    13,014
    3,233
    A 4.7MΩ resistor will likely work, but to be safe use a 3.3MΩ resistor in series with a 1MΩ resistor.
     
  4. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    Your schematic is upside down.
    The positive supply should be at the top and ground should be at the bottom.

    The CD4011 quad NAND is a digital electronic IC, not a box. It should have the 4 NAND gates drawn.

    Your IC pins are shown from the bottom, not from the top which is normal.

    Never mind. It is not yours. You copied it. I also found it in google.

    The value of the 4.3M resistor (not 4.3m) and the 0.1uF capacitor simply determine the beeping rate of the transmitter tone. It is about one beep per second.

    If you use 3M3 (not 3m3) then the beeps will be a little faster and if you use 4M7 (not 4m7) then the beeps will be a little slower.
     
  5. MrChips

    Moderator

    Oct 2, 2009
    12,442
    3,361
    Ah! Then in that case, use 1MΩ which we all have tons laying around and change the value of the capacitor.
     
  6. markosillypig

    Thread Starter Active Member

    Jul 21, 2008
    184
    0
    schematic is up dated a little with the pin orientation the right way
    so is this the correct way and should this circuit work for me ?
    cheers
     
    Last edited: Feb 5, 2013
  7. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    Yes, that is better, thank you.
    Except the text is .....

    As we said, the 4.3M resistor can be 1M, 2.2M, 3.3M, 4.7M, 5.6M, 6.8M or 10M.
     
    markosillypig likes this.
  8. markosillypig

    Thread Starter Active Member

    Jul 21, 2008
    184
    0
    thanks will alter all text later when i do a better schematic of it
    and a PCB diagram and i have taken note on the 4M3 resistor
    cheers
     
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