It is standard practice to carry the flow of electricity to a solenoid through ______.

• A. relay contacts
• B. coils
• C. transistors
• D. diodes

Answer: (A)

Power to a solenoid is typically routed through relay contacts because a relay provides a robust, isolated switch that can handle the high current required by the solenoid while keeping the control circuit safe. The solenoid itself is a coil, so the energizing current should flow through a switching device—not through another coil. While transistors can drive solenoids in some designs, relay contacts are the standard choice in many systems due to their simplicity, reliability, and clear separation between control and power circuits. Diodes, on the other hand, are used to protect against back‑EMF by clamping voltage across the coil, not to carry the main energizing current. So the practical path for energizing a solenoid is through relay contacts.