[sdiy] AR envelope and 4066

[Simon Brouwer]

Hi Ryan, Gabriel,

gabriel at lindeborg.org wrote:

>Hi Ryan!
>
>You do realise that you by closing the 4066 switch and setting the Attack
>to 0ohms will have a hefty current running thru the 4066 until the cap is
>fully charged? Sort of like shortening the 15V to ground...
>
>//Gabbe
>
>  
>
According to the data sheet the maximum DC current into any pin is 10
mA, and the on resistance of a switch @15V is 125 ohms, so in your case
the peak current is 120 mA. I would add a 1k5 series resistor.

See: http://www.ee.washington.edu/stores/DataSheets/cd4000/cd4066.pdf

>>hi all,
>>
>>I've just buiit a simple AR or AD envelope generator. it's based on ray
>>wilson's design, but now different. the schematic is here:
>>http://www.sdiy.org/destrukto/temp/ad-ad_eg.pdf
>>
>>but, there is something terribly wrong with it. It works at first, but
>>when I adjust the attack (and possibly decay) pot to 0ohm, the CD4066
>>gets hot burns. I've blown 2 cd4066's already. Should I be limiting the
>>current into the 4066? I've looked at a few designs that use a 4066 and
>>one has 47ohm resistors in series with the attack/release pots, and the
>>other does not.
>>
>>it is possible that there is a short somewhere on the board. I made it
>>on a CNC milling machine and small bits of copper sometimes cause
>>shorts. I have went over the whole board with an exacto knife and
>>continuity tester, but still could have missed something.
>>
>>this was supposed to be a test board. I planned to have PCBs made if it
>>worked out, but I can't say if the problem is with the design or the
>>construction so I'm not sure what to do. any ideas on the design?
>>
>>-ryan
>>
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>>
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-- 
Vriendelijke groet,
Simon Brouwer.

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