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Old November 30th 10, 01:52 AM posted to rec.radio.amateur.homebrew
Dave M[_3_] Dave M[_3_] is offline
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First recorded activity by RadioBanter: Mar 2010
Posts: 30
Default Multifunction IC

Andreu wrote:
Hello, first thanks for your comments and suggestions, and
sorry for my tri-post...sometimes thunderbird combined with my nerves
make for such nasty things.
Regarding the IC, please look at:

http://www.qsl.net/va3iul/Homebrew_R...eyer_W9HFM.gif

and you will see a CW keyer build around a single IC (MC787P in this
case). So yes, such a rare beasts exist ...lol. They consist of a J-K
flip-flop and 2 or 3 gates. The problem is that they are dated back
from the 70's and doesn't exist anymore, so I was looking for a more
current one. Thanks anyway and happy new year !!

Andrew.


You might be able to duplicate the circuit by using CMOS chips instead of
hunting forever for the MC787P. The 4009 (hex inverter) or 4010 (hex
buffer). Due to the way they're drawn on the schematic, I'm assuming that
all three of the gates in the MC787P are inverting, so you would use the
4009 for those. A 4027 could be used for the JK flipflop. The CMOS chips
will work down to the 3.6 volts specified, so that shouldn't be a problem.
The 1N270 diodes are germanium signal diodes, and are still available. The
2N4888 transistor replacement is the NTE288.
You should be able to find all from Mouser.com.
Good luck with your project.

--
David
dgminala at mediacombb dot net