The δ1 relay-based R-2R stereo attenuator

### Resistor value calculator

Input:

 Relays 8 7 6 5 Step size (dB) 1.0 0.5 0.1 Zatt (KΩ) Zload (KΩ) Resistor standard E48 E96 E192 Output format graphic table

Output:    Maximum attenuation: −127.5dB

K0: −0.5dB
A: −0.50dB
Z: 25.0KΩ
 RS01.40KΩ RP0422KΩ
K1: −1.0dB
A: −1.01dB
Z: 25.0KΩ
 RS12.74KΩ RP1205KΩ
K2: −2.0dB
A: −1.99dB
Z: 25.0KΩ
 RS25.11KΩ RP297.6KΩ
K3: −4.0dB
A: −4.02dB
Z: 25.1KΩ
 RS39.31KΩ RP343.2KΩ
K4: −8.0dB
A: −7.99dB
Z: 24.9KΩ
 RS415.0KΩ RP416.5KΩ
K5: −16.0dB
A: −15.93dB
Z: 25.0KΩ
 RS521.0KΩ RP54.75KΩ
K6: −32.0dB
A: −31.91dB
Z: 24.9KΩ
 RS624.3KΩ RP6649Ω
K7: −64.0dB
A: −63.96dB
Z: 24.9KΩ
 RS724.9KΩ RP716.0Ω
Term

Z: 24.9KΩ
 RT25.5KΩ

One channel shown, other channel is identical.

Use this to calculate the attenuator resistor values to use with your δ1 board. You specify the following inputs:
Relays
The number of relays you will install (5..8).
Step size
The attenuation per step (1.0dB, 0.5dB or 0.1dB).
Zatt
The attenuator input impedance in KΩ, as seen from the source.
This field accepts a positive number in simple integer, decimal notation or scientific notation.
The load impedance in KΩ, as seen by the attenuator. This is the input impedance of the next amplifier stage.
(e.g., For the α20 , β22 or amplifiers, it is the summed resistance of R1 + R2 on those boards).
This field accepts a positive number in simple integer, decimal notation or scientific notation.
Resistor standard
The EIA standard resistor values to use, as follows:
• E48: 2% tolerance
• E96: 1% tolerance
• E192: 0.5%, 0.25%, 0.1% or better tolerance
For performance reasons, standards worse than 2% are not listed.
Output format
The calculator's output display format (graphic or table)
The calculator generates the closest specified EIA resistor standard values for RS and RP corresponding to each relay stage, as well as for the RT resistor. It also displays the real attenuation (A) and impedance (Z) of each stage, assuming perfect resistor tolerances.
If the RT resistor does not appear in the calculator's output area, then you should leave it unpopulated.

Resistor calculator program rcalc.cgi 1.12 by AMB, using an AMB-modified backend by LinuxWorks.

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