PASSIVE FILTER

Passive filter calculators

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• Right side: Ηρακλης Δημοπουλος 1983
• filter design guide
• LC filter online calculator

The design procedure is given in the superb book ``Radio-Frequency Electronics by Jon B. Hagen. 

• Page 41

Appendix 4.1. Component values for normalized lowpass filters

• Comparing the Table of J. Hagen book and Dimopoulos calculation for:

2nd order filter, normalized value ~1.414 for the 2 filter elements, is the same for both Hagen/Dimopoulos

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• R1 = 1K ---->1K/0.33W/0805 digikey
• R2 = 1K ---->1K/0.33W/0805 digikey
• C1 = 12pF mouser
• C2 = 29pF --->30pF mouser
• L1 = 29μH --->33μH digikey
• L2 = 12μH digikey

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Confirm results

• another calculator gives same results

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First order RC LP filter

G.Asimakis recipe for rc filter

• C impedance for the -3dB frecuency should be equal to R

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• Using this calculator

File:FILTER-6.jpg

• At 10MHz and C=12pF, R = 1.3K

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• Using this http://sim.okawa-denshi.jp/en/CRtool.php calculator]

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SAME RESULTS:

At 10MHz and C=12pF, R = 1.3K

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• TI calculator

File:FILTER-9.jpg

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2nd Order RC filter

• http://www.electronics-tutorials.ws/filter/filter_2.html

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• 2nd order rc filter calculator

File:FILTER-10.jpg File:FILTER-11.jpg

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Recalculate LC with R = 1.3K

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• C1 = 10 pF mouser
• C2 = 22 pF mouser
• L1 = 39 μH mouser
• L2 = 15 μH ---> DIGIKEY 120mA
• R1 = 1.3K mouser 1/10W---- digikey 1/4W
• R2 = 1.3K

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For 2nd order RC

• C = 10 pF
• R = 1.5K 1/3W mouser