What is indicated if system voltage is present across the terminals of a toggle switch in the "on position"?

When system voltage is present across the terminals of a toggle switch in the "on position," this indicates a normal condition for the switch. In this scenario, the switch is designed to allow current to flow through its contacts when it is in the "on" position. Therefore, voltage being present means that the circuit is likely closed and functioning as intended, permitting the flow of electricity to the connected load. Essentially, the toggle switch is completing the circuit, confirming that it is operating correctly.

If a circuit were open, no voltage would be detected across the terminals because the path for current flow is interrupted. If the switch contacts were open, similar to an open circuit, there would also be no voltage measured across the terminals. Lastly, if the switch contacts were shorted, this would typically result in a complete circuit with minimal resistance, which might show a different kind of voltage reading but not necessarily in the context of it being in the "on" position. Thus, the presence of system voltage in this case confirms normal operation.