NOTE 3 Where there are capacitors across the insulation under test (for example, radio frequency filter capacitors), it is recommended that d.c. test voltages are used. NOTE 4 Components providing a d.c. path in parallel with the insulation to be tested, such as discharge resistors for filter capacitors, voltage limiting devices or surge suppressors, should be disconnected. Where insulation of a transformer winding varies along the length of the winding in accordance with 2.10.1.5, an electric strength test method is used that stresses the insulation accordingly.NOTE 5 An example of such a test method is an induced voltage test that is applied at a frequency sufficiently high to avoid saturation of the transformer. The input voltage is raised to a value that would induce an output voltage equal to the specified test voltage. No test is applied to FUNCTIONAL INSULATION, unless 5.3.4 b) has been selected