Added more clarity to units

docs/source/guide/guide-units.rst

@@ -10,8 +10,7 @@ Units
 scqubits provides a means to set default units for the assumed energies of the quantum systems. These units play a key
 role in :ref:`guide_noise` calculations. They are also used to set axes labels in some plot types.
 
-The currently supported units are: ``GHz``, ``MHz``, ``kHz`` and ``Hz``, with ``GHz`` being the default. 
-A list containing these possible choices can be shown with the ``show_supported_units`` function. 
+The currently supported units can be shown in a list using the function ``show_supported_units``. These are: ``GHz`` (default), ``MHz``, ``kHz`` and ``Hz``. The package also sets Plank's constant $h = 1$, meaning energy and linear frequency have the same units. 
 
 The current units setting can be obtained with the ``get_units`` function. A new setting can be established with the
 ``set_units`` function::
@@ -22,3 +21,24 @@ The current units setting can be obtained with the ``get_units`` function. A new
 
 scqubits also includes several helper functions for convenient conversion from the current system units to and
 from `Hz`. This is accomplished with functions ``to_standard_units`` and ``from_standard_units``.
+
+
+Examples
+--------
+
+Let's start by creating a Transmon from a given $E_J, E_C$. Written in code looks like::
+
+   scqubits.set_units('GHz')
+
+   tmon = scqubits.Transmon(EJ=30.02,       # Linear GHz
+                            EC=1.2,         # Linear GHz
+                            ng=0.3,
+                            ncut=31)
+   energies = tmon.eigenvals(evals_count=3) # Outputs in Linear GHz
+
+Now let's do the inverse. For a given qubit's resonsant frequency $f_{01}$ and anharmonicity $\\alpha$$, determine $E_J, E_C$. Written in code looks like::
+
+   qubit_01_freq = 3.882           # Linear GHz
+   qubit_anharmonicity = -0.180    # Linear GHz
+
+   EJ, EC = TunableTransmon.find_EJ_EC(E01=qubit_01_freq, anharmonicity=qubit_anharmonicity) # Outputs in Linear GHz