Which of the following is considered one of the basic components of most PLCs?

A power supply is essential for any programmable logic controller (PLC) as it provides the necessary electrical power to operate all components of the system. Without a stable and adequate power supply, the PLC cannot function properly. It ensures that the processor and all connected devices receive the correct voltage, which is critical for the reliable operation of the entire system. The power supply also plays a role in converting incoming electrical power into the form required by the internal components, helping to maintain the various operations, logic processing, and inputs/outputs of the PLC.

In contrast, while switching modules, heater modules, and indicator lights may be included in certain PLC applications, they are not fundamental components required for the basic operation of a PLC. These components serve specific functions based on the application but are not universally present in all PLC configurations. The power supply stands out as a universally required component across all PLC systems.