Is it true that anytime DC voltage is applied between a conductor and insulator, an electrical charge will be held between them?

When a direct current (DC) voltage is applied between a conductor and an insulator, an electric field is created between them. This electric field can lead to the accumulation of electrical charge at the interface of the two materials, especially at the surface of the insulator. This phenomenon occurs because the conductor allows the movement of charges freely, while the insulator restricts this movement. As a result, some charges from the conductor may induce a polarization of charges in the insulator, and this can lead to a static charge being held between the conductor and the insulator.

This interaction is a fundamental principle in electrostatics and applies regardless of whether the insulation is particularly "good" or whether the conductor is actively energized. Good insulation might mitigate leakage currents or help maintain a stable charge for a longer duration, but the mere application of a DC voltage will result in charge being held due to the nature of the electric field. Similarly, the status of the conductor being energized does not influence the initial occurrence of charge accumulation when voltage is present.

Thus, the statement that anytime DC voltage is applied between a conductor and insulator, an electrical charge will be held between them, is true in the context of established electrostatic principles.