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November 3rd, 2009, 06:10 PM
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#1 |
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Trustee
Join Date: Aug 2008
Location: New York
Posts: 1,073
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-20dB pad values
I need to construct a simple 'L' pad within a special connection cable. The primary is unbalanced at about 0dBu nominally. Can someone tell me what the R1 & R2 values should be to get approx. 20-25db of attenuation. Unbalanced to unbalanced. Thanks.
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November 4th, 2009, 11:19 AM
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#2 |
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Regular Crew
Join Date: Mar 2006
Location: Leesburg, Fla
Posts: 83
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20db Pad
20 dbv = a gain of 10. You want to have 1000 ohms as R1 & 100 ohms as R2. The resistors should be 1/4 watt 5% tolerance; these are carbon film resistors. You might see if your local radio shack still carries resistors.
signal in __1000________ Signal out. 100 ground The 1000 ohm resistor is in series with the incoming signal; the 100 ohm goes from the secondary side of the 1000 ohm resistor to ground. This will give you a 2o db loss in signal voltage. |
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November 4th, 2009, 12:07 PM
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#3 |
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Trustee
Join Date: Aug 2008
Location: New York
Posts: 1,073
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Thanks Bill,
I've built many pads, I just can't seem to figure out the resistor value equations. Duh. ----------------- I had a 1k and 100 ohm in my collection of odds & ends already so a trip to the Shack O' Shame was unnecessary. Soldered them in.. works great. Thanks again. Last edited by Rick Reineke; November 4th, 2009 at 03:59 PM. Reason: Addendum |
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November 5th, 2009, 11:39 AM
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#4 |
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Regular Crew
Join Date: Mar 2006
Location: Leesburg, Fla
Posts: 83
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20 DB Pad
Hi Rick: Glad to hear it worked out for you.
Bill W. |
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