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Chip Amps Amplifiers based on integrated circuits

What to do about mismatched IC footprints?
What to do about mismatched IC footprints?
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Old 9th December 2019, 12:17 PM   #21
edbarx is offline edbarx  Malta
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Quote:
Originally Posted by edbarx
If anyone can provide a simple one transistor circuit for that, please post. Pin 8 requires a current >= 0.5mA to flow out towards the negative rail for mute to be disabled.
Please, do not reply for this. I designed a simple delay circuit based on current source topology. A current source guarantees mute current remains constant.
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Last edited by edbarx; 9th December 2019 at 12:46 PM.
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Old 10th December 2019, 03:08 PM   #22
edbarx is offline edbarx  Malta
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Please, someone who happens to know, reply to this simple question, yet google.com couldn't link to an answer!

I am building a PCB for LM3886 amplifier but I have no idea how I must connect the input electrolytic capacitors.

Which capacitor terminal, anode or cathode should be connected to the non-inverting input? A 1k resistor is between user input and non-inverting terminal, a 22k resistor is between user input and ground. The capacitor will be connected to user input. Which capacitor terminal goes there?

Google is only good to give adverts and links to buy ready made products.
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Old 11th December 2019, 12:13 AM   #23
PRR is offline PRR  United States
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> google.com couldn't link to an answer!
> Which capacitor terminal, anode or cathode should be connected to the non-inverting input?


First G-hit is the LM3886 data sheet, font of all wisdom.

It obviously depends if you are powering bipolar supply or single supply.

For single supply Fig 3 is your guide.

For bipolar supply, look at the basic operation. Both inputs should sit at "zero" DC. The datasheet doesn't even use capacitors. I'm paranoid so I like caps. With near-zero DC voltage a Film cap would be preferred; electros like some steady DC on them. However modern electros don't need it so much. Bi-Polar electros are available. However for the expected <1V DC here, plain electros will work *either way*. (It takes more than a Volt of reverse bias to break down.)

Finally, study the Internals, page 7. The inputs are NPNs. If you connect a resistor to zero-volt ground, the base current will drift the bases slightly -negative-. This can guide your cap polarity. How much? Input bias current is as-much-as 1uA. Given 22k resistor, this is 22mV.
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Old 12th December 2019, 01:53 AM   #24
edbarx is offline edbarx  Malta
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Quote:
Originally Posted by PRR
For bipolar supply, look at the basic operation. Both inputs should sit at "zero" DC. The datasheet doesn't even use capacitors. I'm paranoid so I like caps.
Code:
$ dict paranoid
3 definitions found

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  paranoid \par"a*noid`\, a.
     1. (Med.) Affected with paranoia; as, a paranoid
        schizophrenic.
  
     Syn: paranoiac.
          [PJC]
  
     2. Suffering from delusions of being persecuted by the
        conspiratorial actions of others; having an unwarranted
        suspicion of the motives of others; -- used loosely in a
        negative sense, not as a medical term; as, just because
        you're paranoid doesn't mean they are not out to get you.
        [Colloq.]
        [PJC]

From WordNet (r) 3.0 (2006) [wn]:

  paranoid
      adj 1: suffering from paranoia
      n 1: a person afflicted with paranoia [syn: {paranoid},
           {paranoiac}]

From Moby Thesaurus II by Grady Ward, 1.0 [moby-thesaurus]:

  25 Moby Thesaurus words for "paranoid":
     brain-damaged, brain-injured, catatoniac, catatonic, certifiable,
     certifiable case, disturbed, manic-depressive, mental, mental case,
     mentally ill, mentally sick, neurotic, paranoiac, psycho,
     psychopath, psychopathic, psychopathic case,
     psychopathic personality, psychotic, schiz, schizo, schizoid,
     schizophrenic, schizy
Shame on you.
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Old 12th December 2019, 02:15 AM   #25
ubergeeknz is online now ubergeeknz  New Zealand
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Quote:
Originally Posted by edbarx View Post
Code:
$ dict paranoid
3 definitions found

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  paranoid \par"a*noid`\, a.
     1. (Med.) Affected with paranoia; as, a paranoid
        schizophrenic.
  
     Syn: paranoiac.
          [PJC]
  
     2. Suffering from delusions of being persecuted by the
        conspiratorial actions of others; having an unwarranted
        suspicion of the motives of others; -- used loosely in a
        negative sense, not as a medical term; as, just because
        you're paranoid doesn't mean they are not out to get you.
        [Colloq.]
        [PJC]

From WordNet (r) 3.0 (2006) [wn]:

  paranoid
      adj 1: suffering from paranoia
      n 1: a person afflicted with paranoia [syn: {paranoid},
           {paranoiac}]

From Moby Thesaurus II by Grady Ward, 1.0 [moby-thesaurus]:

  25 Moby Thesaurus words for "paranoid":
     brain-damaged, brain-injured, catatoniac, catatonic, certifiable,
     certifiable case, disturbed, manic-depressive, mental, mental case,
     mentally ill, mentally sick, neurotic, paranoiac, psycho,
     psychopath, psychopathic, psychopathic case,
     psychopathic personality, psychotic, schiz, schizo, schizoid,
     schizophrenic, schizy
Shame on you.
Context is everything. Paranoid in this context simply means "do not trust" as in, prefer to take additional steps to be safe in all operating conditions, than not.
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Old 12th December 2019, 02:32 AM   #26
PRR is offline PRR  United States
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Quote:
Originally Posted by edbarx View Post
...Shame on you.
I do not understand why you personally attack (try to shame) me. I am suspicious of your motives.
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File Type: jpg paranoia.jpg (20.1 KB, 15 views)
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