Resistor value calculator
for constructing shunt attenuators with up to 75 steps.

(c) 2020 - Avaudio copy

(Click here for a resistor string attenuator calculator)

Potential divider resistors Rx and Ry as shown:

Enter series value of attenuator : ohms. (= Rx)
Enter number of steps (77 max):

Enter attenuation required for each step:
-- Step 01 : dB. -- Step 02 : dB. -- Step 03 : dB.
-- Step 04 : dB. -- Step 05 : dB. -- Step 06 : dB.
-- Step 07 : dB. -- Step 08 : dB. -- Step 09 : dB.
-- Step 10 : dB. -- Step 11 : dB. -- Step 12 : dB.
-- Step 13 : dB. -- Step 14 : dB. -- Step 15 : dB.
-- Step 16 : dB. -- Step 17 : dB. -- Step 18 : dB.
-- Step 19 : dB. -- Step 20 : dB. -- Step 21 : dB.
-- Step 22 : dB. -- Step 23 : dB. -- Step 24 : dB.
-- Step 25 : dB. -- Step 26 : dB. -- Step 27 : dB.
-- Step 28 : dB. -- Step 29 : dB. -- Step 30 : dB.
-- Step 31 : dB. -- Step 32 : dB. -- Step 33 : dB.
-- Step 34 : dB. -- Step 35 : dB. -- Step 36 : dB.
-- Step 37 : dB. -- Step 38 : dB. -- Step 39 : dB.
-- Step 40 : dB. -- Step 41 : dB. -- Step 42 : dB.
-- Step 43 : dB. -- Step 44 : dB. -- Step 45 : dB.
-- Step 46 : dB. -- Step 47 : dB. -- Step 48 : dB.
-- Step 49 : dB. -- Step 50 : dB. -- Step 51 : dB.
-- Step 52 : dB. -- Step 53 : dB. -- Step 54 : dB.
-- Step 55 : dB. -- Step 56 : dB. -- Step 57 : dB.
-- Step 58 : dB. -- Step 59 : dB. -- Step 60 : dB.
-- Step 61 : dB. -- Step 62 : dB. -- Step 63 : dB.
-- Step 64 : dB. -- Step 65 : dB. -- Step 66 : dB.
-- Step 67 : dB. -- Step 68 : dB. -- Step 69 : dB.
-- Step 70 : dB. -- Step 71 : dB. -- Step 72 : dB.
-- Step 73 : dB. -- Step 74 : dB. -- Step 75 : dB.
-- Step 76 : dB. -- Step 77 : dB.

Results:
Step 1, Attenuation = Infinity dB, Rx = 33000 ohms, Ry = 0 ohms. Step 2, Attenuation = 75 dB, Rx = 33000 ohms, Ry = 6 ohms. Step 3, Attenuation = 74 dB, Rx = 33000 ohms, Ry = 7 ohms. Step 4, Attenuation = 73 dB, Rx = 33000 ohms, Ry = 7 ohms. Step 5, Attenuation = 72 dB, Rx = 33000 ohms, Ry = 8 ohms. Step 6, Attenuation = 71 dB, Rx = 33000 ohms, Ry = 9 ohms. Step 7, Attenuation = 70 dB, Rx = 33000 ohms, Ry = 10 ohms. Step 8, Attenuation = 69 dB, Rx = 33000 ohms, Ry = 12 ohms. Step 9, Attenuation = 68 dB, Rx = 33000 ohms, Ry = 13 ohms. Step 10, Attenuation = 67 dB, Rx = 33000 ohms, Ry = 15 ohms. Step 11, Attenuation = 66 dB, Rx = 33000 ohms, Ry = 17 ohms. Step 12, Attenuation = 65 dB, Rx = 33000 ohms, Ry = 19 ohms. Step 13, Attenuation = 64 dB, Rx = 33000 ohms, Ry = 21 ohms. Step 14, Attenuation = 63 dB, Rx = 33000 ohms, Ry = 23 ohms. Step 15, Attenuation = 62 dB, Rx = 33000 ohms, Ry = 26 ohms. Step 16, Attenuation = 61 dB, Rx = 33000 ohms, Ry = 29 ohms. Step 17, Attenuation = 60 dB, Rx = 33000 ohms, Ry = 33 ohms. Step 18, Attenuation = 59 dB, Rx = 33000 ohms, Ry = 37 ohms. Step 19, Attenuation = 58 dB, Rx = 33000 ohms, Ry = 42 ohms. Step 20, Attenuation = 57 dB, Rx = 33000 ohms, Ry = 47 ohms. Step 21, Attenuation = 56 dB, Rx = 33000 ohms, Ry = 52 ohms. Step 22, Attenuation = 55 dB, Rx = 33000 ohms, Ry = 59 ohms. Step 23, Attenuation = 54 dB, Rx = 33000 ohms, Ry = 66 ohms. Step 24, Attenuation = 53 dB, Rx = 33000 ohms, Ry = 74 ohms. Step 25, Attenuation = 52 dB, Rx = 33000 ohms, Ry = 83 ohms. Step 26, Attenuation = 51 dB, Rx = 33000 ohms, Ry = 93 ohms. Step 27, Attenuation = 50 dB, Rx = 33000 ohms, Ry = 105 ohms. Step 28, Attenuation = 49 dB, Rx = 33000 ohms, Ry = 118 ohms. Step 29, Attenuation = 48 dB, Rx = 33000 ohms, Ry = 132 ohms. Step 30, Attenuation = 47 dB, Rx = 33000 ohms, Ry = 148 ohms. Step 31, Attenuation = 46 dB, Rx = 33000 ohms, Ry = 166 ohms. Step 32, Attenuation = 45 dB, Rx = 33000 ohms, Ry = 187 ohms. Step 33, Attenuation = 44 dB, Rx = 33000 ohms, Ry = 210 ohms. Step 34, Attenuation = 43 dB, Rx = 33000 ohms, Ry = 235 ohms. Step 35, Attenuation = 42 dB, Rx = 33000 ohms, Ry = 264 ohms. Step 36, Attenuation = 41 dB, Rx = 33000 ohms, Ry = 297 ohms. Step 37, Attenuation = 40 dB, Rx = 33000 ohms, Ry = 333 ohms. Step 38, Attenuation = 39 dB, Rx = 33000 ohms, Ry = 374 ohms. Step 39, Attenuation = 38 dB, Rx = 33000 ohms, Ry = 421 ohms. Step 40, Attenuation = 37 dB, Rx = 33000 ohms, Ry = 473 ohms. Step 41, Attenuation = 36 dB, Rx = 33000 ohms, Ry = 531 ohms. Step 42, Attenuation = 35 dB, Rx = 33000 ohms, Ry = 597 ohms. Step 43, Attenuation = 34 dB, Rx = 33000 ohms, Ry = 672 ohms. Step 44, Attenuation = 33 dB, Rx = 33000 ohms, Ry = 756 ohms. Step 45, Attenuation = 32 dB, Rx = 33000 ohms, Ry = 850 ohms. Step 46, Attenuation = 31 dB, Rx = 33000 ohms, Ry = 957 ohms. Step 47, Attenuation = 30 dB, Rx = 33000 ohms, Ry = 1078 ohms. Step 48, Attenuation = 29 dB, Rx = 33000 ohms, Ry = 1214 ohms. Step 49, Attenuation = 28 dB, Rx = 33000 ohms, Ry = 1368 ohms. Step 50, Attenuation = 27 dB, Rx = 33000 ohms, Ry = 1543 ohms. Step 51, Attenuation = 26 dB, Rx = 33000 ohms, Ry = 1741 ohms. Step 52, Attenuation = 25 dB, Rx = 33000 ohms, Ry = 1966 ohms. Step 53, Attenuation = 24 dB, Rx = 33000 ohms, Ry = 2222 ohms. Step 54, Attenuation = 23 dB, Rx = 33000 ohms, Ry = 2514 ohms. Step 55, Attenuation = 22 dB, Rx = 33000 ohms, Ry = 2847 ohms. Step 56, Attenuation = 21 dB, Rx = 33000 ohms, Ry = 3229 ohms. Step 57, Attenuation = 20 dB, Rx = 33000 ohms, Ry = 3667 ohms. Step 58, Attenuation = 19 dB, Rx = 33000 ohms, Ry = 4171 ohms. Step 59, Attenuation = 18 dB, Rx = 33000 ohms, Ry = 4753 ohms. Step 60, Attenuation = 17 dB, Rx = 33000 ohms, Ry = 5428 ohms. Step 61, Attenuation = 16 dB, Rx = 33000 ohms, Ry = 6215 ohms. Step 62, Attenuation = 15 dB, Rx = 33000 ohms, Ry = 7138 ohms. Step 63, Attenuation = 14 dB, Rx = 33000 ohms, Ry = 8226 ohms. Step 64, Attenuation = 13 dB, Rx = 33000 ohms, Ry = 9519 ohms. Step 65, Attenuation = 12 dB, Rx = 33000 ohms, Ry = 11070 ohms. Step 66, Attenuation = 11 dB, Rx = 33000 ohms, Ry = 12951 ohms. Step 67, Attenuation = 10 dB, Rx = 33000 ohms, Ry = 15262 ohms. Step 68, Attenuation = 9 dB, Rx = 33000 ohms, Ry = 18148 ohms. Step 69, Attenuation = 8 dB, Rx = 33000 ohms, Ry = 21827 ohms. Step 70, Attenuation = 7 dB, Rx = 33000 ohms, Ry = 26640 ohms. Step 71, Attenuation = 6 dB, Rx = 33000 ohms, Ry = 33157 ohms. Step 72, Attenuation = 5 dB, Rx = 33000 ohms, Ry = 42401 ohms. Step 73, Attenuation = 4 dB, Rx = 33000 ohms, Ry = 56421 ohms. Step 74, Attenuation = 3 dB, Rx = 33000 ohms, Ry = 79993 ohms. Step 75, Attenuation = 2 dB, Rx = 33000 ohms, Ry = 127450 ohms. Step 76, Attenuation = 1 dB, Rx = 33000 ohms, Ry = 270451 ohms. Step 77, Attenuation = 0 dB, Rx = 33000 ohms, Ry = Infinity ohms.

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Calculate attenuation for above Rx with a given value of Ry.

Enter Ry : ohms.

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(c) RSS 2007 - Neville Roberts
N C Roberts BSc CEng CPhys FIET MInstP

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