For example, if a load is not energized when it should, a technician should be able to easily identify which switch or switches control that load and then start to troubleshoot the cause. Ladder ...

Four fundamentals include: It's called a ladder diagram because it really does resemble a ladder ... switch), you follow state changes across to the right rail and see, for example, which coils should ...

what makes a ladder diagram especially useful for troubleshooting — you can follow the current flows of control circuits to find what's wrong. The output of one control circuit is often the input to ...