Which of the following is not a basic component of a switch or receptacle?

A lock spring is not typically considered a basic component of a switch or receptacle. The primary components that are essential for the functionality and operation of switches and receptacles include terminal screws, contact plates, and mounting brackets.

Terminal screws are crucial as they are used to secure the electrical wires that provide power to the device. The contact plate is vital because it allows for the electrical connection to be made when the switch is toggled or the receptacle is engaged. The mounting bracket provides stability and supports the switch or receptacle as it is installed into a wall or electrical box.

While a lock spring might be utilized in certain specialty devices to provide tension or maintain a certain functional position, it is not a fundamental component required for the basic operation of switches or receptacles. Thus, identifying the lock spring as the component that does not belong is accurate, as it does not perform an essential role in the basic functionality of these electrical devices.