What is the last step in troubleshooting an electrical circuit when using a schematic?

The last step in troubleshooting an electrical circuit using a schematic is to examine the actual circuit. This step is crucial because, after all previous troubleshooting actions—such as reviewing the schematic, testing voltage levels, and replacing faulty components—this physical inspection provides insight into any discrepancies that may still exist between the schematic design and the actual circuit. By examining the actual circuit, one can identify issues not reflected on the schematic or confirm that repairs made were effective.

This action allows you to see if components are installed correctly, check for loose connections, or identify any unexpected damage or faults not previously detected. It is a comprehensive step that verifies the theoretical corrections made and ensures the circuit functions as intended.