You probably have a general understanding of how current flows in a circuit. But did you know that by brushing up your grasp of how current really works, you could diagnose duty-cycled circuits such as fuel injectors and solve a variety of electrical and solenoid-related puzzles? By using a little logic, you can uncover the roots of baffling symptoms and failures, without resorting to parts-swapping – which is expensive, time-consuming, and boils down to an admission of ignorance.