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#1
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I'm designing a small circuit for use in a QRP transceiver and i would
like to use an IC I have seen somewhere on the net which consist of a single flip-flop and 2 or 3 logic gates (seem to recall they were 3 inverters or 2 OR's and 1 AND. I'ts similar to 74HC7074 but this one is very old. Does samebody remember the part ID for such an IC ? Thanks, Andrew. |
#2
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Thanks John, will think about that ....
Andrew. John W wrote: Andrew, I don't know which IC you mean but you could use a Quad NAND IC (74x08 etc) and use that to make a flip-flop out of two of the NANDs which leaves two NANDs spare for other purposes. JOHN |
#3
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Thanks John, will think about that ....
Andrew. John W wrote: Andrew, I don't know which IC you mean but you could use a Quad NAND IC (74x08 etc) and use that to make a flip-flop out of two of the NANDs which leaves two NANDs spare for other purposes. JOHN |
#4
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Thanks John, will think about that ....
Andrew. John W wrote: Andrew, I don't know which IC you mean but you could use a Quad NAND IC (74x08 etc) and use that to make a flip-flop out of two of the NANDs which leaves two NANDs spare for other purposes. JOHN |
#5
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![]() "Andreu" wrote in message ... Thanks John, will think about that .... Andrew. Andrew, If I were you, I would think about that .... MikeK |
#6
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![]() "amdx" wrote in message ... "Andreu" wrote in message ... Thanks John, will think about that .... Andrew. Andrew, If I were you, I would think about that .... MikeK But not TOO long, as a 74x08 is NOT a NAND function. PA |
#7
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On Nov 16, 8:44*am, SYS1 wrote:
I'm designing a small circuit for use in a QRP transceiver and i would like to use an IC I have seen somewhere on the net which consist of a single flip-flop and 2 or 3 logic gates (seem to recall they were 3 inverters or 2 OR's and 1 AND. I'ts similar to 74HC7074 but this one is very old. Does samebody remember the part ID for such an IC ? Thanks, Andrew. Hey OT: I think what you has seen is a cd4046 internal workings like this TI pdf shows: http://focus.ti.com/lit/an/scha002a/scha002a.pdf or maybe a similar pll. 73 OT de n8zu |
#8
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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. raypsi wrote: On Nov 28, 9:37 am, "John W" wrote: Well spotted - ahh those little grey cells. |
#9
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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. These days, people designing an entire circuit around a single IC use a microcontroller. E.g. a PIC or something from AVR. |
#10
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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 |
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