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Old 28th September 2006, 08:10 AM   #1
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Default BOSOZ (removing P1 P2)

Im finally almost finshed my BOSOZ, Everything powered up and all voltages were fine, I now want to get rid of P1 and P2 input pots that I wired up. Ive searched but I want this concrete in my muddy mind. Thanks in advance and Ill post some pics in a week or so
Thanks!!

Would this be the way to wire it? Any suggestions?

+ Input-----(221 ohm)-------------------------------------Gate
| |
| |
(10 k Ohm) zener
| zener
| |
| |
GND GND
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Old 28th September 2006, 08:13 AM   #2
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Both the 10k resistor and the zeners would be after the 221 ohm resistor in the previous post

Thanks for the help!
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Old 28th September 2006, 08:41 AM   #3
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I would have 221ohm - 10K and zeners to GND - 221ohms - gate.

As far as I remember, the first 221ohms is to separate the two zeners from the input signal source. the second 221ohms is to kill off the parasitic oscillations caused by LR network formed by the inductive lead and high gate resistance.
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Old 28th September 2006, 03:22 PM   #4
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Default Re: BOSOZ (removing P1 P2)

Quote:
Originally posted by raincheck
I now want to get rid of P1 and P2 input pots that I wired up.
Hello, raincheck.
I am no expert on BOSOZ, but I am very good in understanding circuits and schematics.

The purpose of a variable resistor ( trimpot )
is that you can change the voltage level to suit your custom setup.
But if you use same setup all the time, it is better to do as you want to do:
Use 1-2 resistors to replace pot.
Because resistors has often slightly better data than trimpots ( lower noise etc ).

See my attached drawing!
The resistor R18 ( 221 ohm )
is to make sure never will be 0 ohm between +IN and X,
Regardless how you turn trimpot, will be 221 ohm or more between +IN and X.

This first version is if full voltage level will suit your setup.
Equals if The wiper is set at max.
If you prefer a lower input level, see attached circuit in my next post


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Attached Images
File Type: png bosoz-1b.png (6.0 KB, 250 views)
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Old 28th September 2006, 03:28 PM   #5
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Hi.

See my attached circuit!
Here I have replaced 10.000 ohm trimpot
with 3300 + 6800

but can of course be any 2 resistors:
4700 + 4700 will give 50% of voltage level.

In this schematic R18 would not be necessary
to keep 221 ohm, or more, between +IN and X

So could be removed.
But I think you should keep it. It makes no difference.
Nothing will in real life get better by removing R18.
And probably will be easier, from practical reason, to keep it on the PCB board.


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File Type: png bosoz-1c.png (5.9 KB, 234 views)
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