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Crystal oscillator and amplifier purchase

  1. Oct 16, 2014 #1
    in my previous thread i was trying to build a sine oscillator and an amplifier. decided to give up on the idea and purchase. any chips out there that can give me 30-40volts peak to peak. the frequency is not an issue as long as it is above 1 MHz. i guess i can use any crystal oscillator as long as the amplifier can give me 30V. TL08 series seem like a good option.
     
  2. jcsd
  3. Oct 16, 2014 #2

    Baluncore

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    What output impedance will your circuit be driving?
    Will it drive 50 ohm coaxial cable or maybe 400 ohm parallel line?
     
  4. Oct 16, 2014 #3
    im experimenting with wireless power transfer so the circuit will be connected to a transmitter coil. the impedance is not set yet. i will be experimenting, changing the transmitter and the receiver once i get the power supply. thank you
     
  5. Oct 16, 2014 #4

    Baluncore

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    Most experimentation is now done using numerical simulation. With the exception of ISM allocations, the RF spectrum is allocated to important services that must not be interrupted. Your frequency and power levels will be critical to the attention you will receive from the authorities.
    Can you please give more details of your experiment. Over what range do you expect to transfer power?
     
  6. Oct 16, 2014 #5
    i am starting with a small distance of 2 inches and hope to improve it with tests. Yes i will be careful with RF spectrum. Thanks
     
  7. Oct 16, 2014 #6
    Hint,
    To get power transferred, it can be electrostatic coupling, a traveling electro-magnetic wave, or magnetic coupling. An E-M wave needs to be focused which means extraordinarily huge antennas or extraordinarily high frequencies. Very bad and somewhat dangerous to fool with (i.e. making a microwave oven run with the door open dangerous).
    Look at any Tesla coil demonstration and you can see the effects of high voltage coupling.
    The method that works really good over short distances (and I think I posted a circuit on here) is to use a resonate Royer converter to excite an LC tank up to high currents. You need considerable currents in the inductor to get any significant power transfer. i.e. amp per 20-50 mw at 1 inch.
    The current "revolution" in power transfer uses flat transformer halves coupling through a short distance. Again, one half has to maintain a fairly high
    current in the primary to get anything useful from the secondary.
    PS - any jelly-bean op amp, like a TL08x, will not have useful gain at 1MHz. There are plenty of oscillator circuits out there, but they require some skill with transistors or logic used in an analog fashion.
     
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