Question about fig 12-10 first edition

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Question about fig 12-10 first edition please.

Hi Q, I was wondering if you would remember what the DC voltage should be between the output of IC1A and resistor R9, the text dances around the value of the voltage and says words to the effect that it has to be a value to keep the fet in its proper operating region but never mentions what that voltage is .
I built the cct but only had a split 12 volt supply and I got around + 5.3 volts, so I guess with 9v is should be around + 3 to + 4 volts ? thanks.

[Qiaozhi]

Question about fig 12-10 first edition please.

Hi Q, I was wondering if you would remember what the DC voltage should be between the output of IC1A and resistor R9, the text dances around the value of the voltage and says words to the effect that it has to be a value to keep the fet in its proper operating region but never mentions what that voltage is .
I built the cct but only had a split 12 volt supply and I got around + 5.3 volts, so I guess with 9v is should be around + 3 to + 4 volts ? thanks.

PI-2 needs to be run from a 9V supply. It says in the text on page 166 that the PIC operates from half the supply voltage, and that attempting to use a 12V supply could damage the micro.

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Thanks but the only part I made was the preamp to try and figure out what voltage should be at the preamp out so the fet can work, all I made was IC1a,d3,r4,r5,r6,r7,r8, that should be enough to give me the voltage going to the fet (with the fet off)