In ladder diagrams, which devices are placed on the right side?

• A. Input devices
• B. Output devices
• C. Memory devices
• D. Control relays

Answer: (B)

In ladder diagrams, the path from left to right represents turning conditions into an action. The left side holds the input conditions (sensors, pushbuttons, switches) that can be true or false. When those conditions are met, current flows toward the right, energizing whatever is placed there. That right-side element is the output device—the actuator or indicator that performs the action, like a motor, lamp, or other controlled device. Think of the right side as the place where the results of the logic actually show up in the plant. For example, a normally open start button on the left closing allows current to energize the output coil on the right, which turns on a motor. Internal memory or relay coils can also appear on the right, but the key idea is that outputs reside on the right.