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Somebody help me please...

U

Umar Munawwir

Jan 1, 1970
0
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?
 
R

Robert Baer

Jan 1, 1970
0
Umar said:
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?

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.
 
R

Rob

Jan 1, 1970
0
Robert Baer said:
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.

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