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Somebody help me please...

Discussion in 'General Electronics' started by Umar Munawwir, Sep 12, 2003.

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  1. I am making a 2MHz ultrasonic transmitter using CMOS 4047,4040,4047
    and 4081 (RF wave), the output from 4081 is 12V, but it can't drive
    the the transducer yet. So, i use current booster (2N2222 & 2N2907)
    and it can drive the transducer. But the next problem is the output
    voltage is too low. I need higher voltage about 24-36V.
    What should I do? I've used MOSFET before and put the load at source
    but the out put voltage remain unchange or still 12 V.
    Please help me...
    I need higher voltage no more than 36 V but with high current too.
    What should I do?
  2. Robert Baer

    Robert Baer Guest

    Whenever i see "CMOS" i think of the old RCA slow stuff and then ask
    "don't you mean KHz?".
    Using the source of a FET gives a voltage gain near one, so the load
    voltage will be about the same as the gate drive (the 12V you mention).
    However, if this is a CW or FM signal, driving the gate with source to
    ground, and having a tuned drain with (say) a 50V supply, then one has
    something like a class "C" amplifier and one could get hunderds of volts
    (given the right FET and supply).
    A number of transducers are capacitive, so make it part of that tuned
    circuit - to get a large displacement current.
  3. Rob

    Rob Guest

    Did that solve the problem? How much current (or power) do you need? Rob -
    Sept 19
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