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Old 27th April 2006, 07:44 AM   #1
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Default LM386 RF suppression

I built the LM386 utility amplifier based off the circuit provided in the manufacturers PDF file and am experiencing radio interferance. I don't know if it's short wave or what cuz there are these german people...some times French or British...or worst of all religious sermons!

Anyway, how does one filter out this gook?
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Old 27th April 2006, 11:54 AM   #2
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LR-circuit on the output and 220pF across the two inputs (+/-) of the LM3886.

Thomas
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Old 29th April 2006, 05:11 PM   #3
mctylr is offline mctylr  Canada
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Default Use the datasheets

See page 6 of National's LM386 datasheet.

For the lazy:
http://www.national.com/ds/LM/LM386.pdf
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Old 2nd May 2006, 05:41 AM   #4
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Hey thanks for the replies and help, I knew it was going to be a simple capacitor filtering solution but none of the values I tried worked. Do I really need to go so far as to adding the LR circuit though?
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Old 4th May 2006, 07:43 AM   #5
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The need of the LR-circuit is very dependent on the load (including cable) that the amplifier sees, so start without and see how it works. A small powerresistor will actually have the same effect (say 0R2/5 w)

Have fun

Thomas
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