TI-H: 92 acceleration

To: ti-hardware@lists.ticalc.org
Subject: TI-H: 92 acceleration
From: "Richard Piotter" <richfiles1@hotmail.com>
Date: Wed, 19 Nov 1997 16:40:30 PST
Reply-To: ti-hardware@lists.ticalc.org
More crashproof way of TI-92 acceleration explained at end...
_____________________________________________________________

>:adding capacitors in series adds their capacitance in the following 
way:
>:            1
>: --------------------------
>:  1/C1 + 1/C2 + ... + 1/CN
>:

>:Putting the capacitors in parallel would add their capacetance C1 + C2 
+ C3..


>      switch
     |   |    |	
>	 8pf |   22pf \	  	
>	 |   |   16pf  - total (or so I thought) of 47 in series
>	 |   |   7pf  /
>	 |   |    |
     | (C11)  \_
     \___|______|   (8pf and 47pf total join here
         |      |   leading to other side of C11)  
>	     |		|   (from middle pole of switch)
>	     |       \____________
>	     |                    \
>	     \_________0 (C11) 0__/
>
>
If you're doing that, then why not put C11 (old one) where the three are 
and the 8 pf where it is.

like this:

>      switch
     |   |    |	
>	 8pf |   47pf (C11, the original cap)	
>	 |   |    |
     |   |    \_
     \___|______|   (8pf and 47pf total join here
         |      |   leading to other side of C11)  
>	     |		|   (from middle pole of switch)
>	     |       \____________
>	     |           Board    \
>	     \_________0 (C11) 0__/

But I'm not sure if the switch arrangement is wise. Less than 8 pf is 
not good, but there is a split second where there is no capacitor 
connected when you switch between speeds. Is this safe??? I think it 
would be wise to connect like this:

          __8pf_   8+30=38. Add the 8 that's always connected
>	     |_30pf_|  and it becomes 38+8=46. The wires add a
         |      |  little capacitance, so it's about 47pf!
       switch   |
         |      |  This way, you NEVER have less than 8pf!
>	     |_8pf__|______
>	     |             \   Use a SPST switch, not the SPDT.
         |    Board     |  (cheaper & DIP can be used)
>	     \__0 (C11) 0__/

Richard Piotter

E-Mail:
richfiles1@hotmail.com
richfiles@usa.net

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