Constant impedance relay-resistor logarithmic attenuator

[Adams_Leo]

0-47dB range

quiet

precise...resistors 0.1% unless otherwise noted

Do the both sides Constant impedance 10K,right?

 

[DUG]

Do the both sides Constant impedance 10K,right?

2K

 

[Adams_Leo]

> if I want Constant source impedance....,if I want to Constant output impedance,

For completeness:

If BOTH ends must be constant, for at least 90 years there has been a standard plan, like the attached.

The plans in this thread give-up the constant Z both-ends to get *half* the number of switch actions. In audio we can usually do that. Gain (impedance changes) is cheap.

This particular plan is valued for 50 Ohms. Scaling to another standard is trivial.

this is good idea,and each stage is the T-PAN mode.thansks for you sharing this information.

 

[Adams_Leo]

here is the layout for the Constant input and output impedance.Left and right channels are controlled separately.I plan to use Arduino for the MCU to control it. NLU2803 protect diodes is not stable and it is very easy to broken so I have add extra diodes.