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Old 11th February 2010, 02:30 PM   #1
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Default Diode across an op-amp???

Why in the world would they put a diode across an op-amp like this??
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Old 11th February 2010, 02:49 PM   #2
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The diode protects the input to the op amp, in the event that fast negative going input is applied. You should not need the diode for all amps, just some that are susceptible.
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Old 11th February 2010, 02:54 PM   #3
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this is in a PA amplifier. wouldn't half the waveform always be shorted anytime the signal level gets above .7V?? as this is the first stage of the amp, I would think the signal level to be above .7v but I am not sure?
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Old 11th February 2010, 03:19 PM   #4
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there is no voltage difference between input and output of that unity gain buffer, hence the diode doesn't conduct under normal operating conditions.
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Old 11th February 2010, 03:21 PM   #5
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OH YEA! yea yea I wasn't thinking of it that way. ok i get it now. I am so used to seeing diodes across op-amps in guitar distortion boxes that I wasn't thinking about it.

Last edited by Zero Cool; 11th February 2010 at 03:23 PM.
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