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This page is to illustrate the APP of R-2R Digital Analog Converter project
The related lab is Lab III - Thevenin and Norton Equivalent Circuits

Here is the APP in .nb:    and .cdf

Here is the data analysis APP.


An R-2R ladder network can be constructed like a ladder: by adding the ladder steps one at a time.
1-bit ladder is obviously just a trivial voltage divider.





Analysis of a multi-step ladder is actually simple by using recursion method with Thevenin's equivalent circuit (TEC) theorem. Numerically, it is also done recursively: a simple formula calculating the output TEC for a given input TEC and a single ladder step. That output becomes input again with an additional ladder step and the process continues.


The ladder can actually be useful to study the concept of mesh current as well. Observe how the currents flow from sources (bit that are ON) to sinks (bits that are OFF). Observe Kirchhoff's current law at the nodes. The current magnitude is represented by the width of the vector. The wider a vector, the larger its current.
The vertical bars represent the node voltages. In the APP, you can click on/off the displays of node voltages, mesh currents and its animation.




This illustrate how the ladder works as numerical values from 1 to 255 are input into the ladder. The right hand side graph shows the node voltages from low bits (bottom) to high bits (top). The voltages that vertically shifted for clarity.

This is similar to the above except that the inputs are not numbers but ASCII 7-bit binary code. The highest bit is simply set to 0.