[Diy_efi] schematic critique

[Toyota Supra]

hi bill!

ok, i deleted R4 and C3, i ran the collector of the transistor to 12vDC, (i 
don't know if it'll require the 8v or the 12v, but i chose 12v because it 
will be driving a 30amp bosch automotive relay, hopefully that was the right 
decision) . i changed R5 to 1k

now, here is where i am not sure i understand, i have D1 and D2, one allows 
negative to flow to positive, and the other, positive to flow to negative. 
i'm not sure which type of kickback the relay will have, but they are on the 
positive side of the coil? i am guessing i only need 1 diode instead of two, 
but let me know.

i also have two renditions, links seen here

with the 47k potentiometer
http://68.7.7.84:8080/schematics/schematic4.jpg
http://68.7.7.84:8080/schematics/schematic4.psd

without the 47k potentiometer
http://68.7.7.84:8080/schematics/schematic5.jpg
http://68.7.7.84:8080/schematics/schematic5.psd


it sounds to me, as if you would like me to stick with the "schematic5" 
rendition, but i wanted to put up both options and get your opinion for 
sure, number 4 might be used to take a voltage signal and drop it to the 
desired 3.2vDC reference signal???? .... thanks soooo much for the guidance 
throughout this

-j






From: Bill Washington <bill.washington at nec.com.au>
>Reply-To: List for general do-it-yourself EFI talk <diy_efi at diy-efi.org>
>To: diy_efi at diy-efi.org
>Subject: [Diy_efi] schematic critique
>Date: Wed, 19 Feb 2003 09:52:19 +1100
>
>J,
>    Perhaps my suggestions weren't very clear, so I'll try to clarify:
>
>1. The diode you have added is connected back to front. (Diode =>  ANODE 
>-|>|- CATHODE)
>2. the Collector of the transistor should go to +8 or +12 V supply 
>depending on the relay's coil voltage, not to the + input of the Opamp!
>3. change R5 to 1k Ohm
>4. delete C3, Opamp inputs must not be capacitively coupled,
>5. With the above changes, the circuit will work opposite to description IE 
>#1>~#2 => #3 = 8V..... #1<~#2 => #3 = 0V
>6. R3 adds hysteresis, therefore the switching point will not be when 
>#1=#2.
>7. Delete R4, it serves no purpose.
>
>If #2 is directly connected to U1 pin 4, #3 will switch to 8V when #1 rises 
>above 3.232Vand remain there until #1 drops below 3.152V, at which time #3 
>will switch back to 0V.
>
>I hope this helps.
>Regards
>Bill
>
>
>
>
>>Date: Mon, 17 Feb 2003 21:51:01 -0500 From: "Toyota Supra" 
>><turbosupramk3 at hotmail.com> To: diy_efi at diy-efi.org Subject: Re: [Diy_efi] 
>>schematic critique (???) Message-ID: 
>><BAY2-F166I063RA5C2d00030b5c at hotmail.com> Content-Type: text/plain; 
>>format=flowed MIME-Version: 1.0 Precedence: list Reply-To: List for 
>>general do-it-yourself EFI talk <diy_efi at diy-efi.org> Message: 7 hey bill, 
>>i have modified the circuit per your and some others advice, i must say 
>>that i am thoroughly confused now with the different versions that it has 
>>went through, so i am relying that this will function, else i won't know 
>>which values to alter ??? :) here is the latest photoshopped schematic, 
>>version 3.0 http://68.7.7.84:8080/schematics/schematic3.psd 
>>http://68.7.7.84:8080/schematics/schematic3.jpg are the values and 
>>placements of the components on par as well? lmk, thanks for the help all 
>>-j
>>
>>>>Fro
>>>
>
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