Motion Sensing Night Light

You may think that the motion sensing light at night is better because it is outside most of the time. But, for motion detection, would not need a circuit and a chip or something? and therefore, it would be necessary to convert alternating current, it would be necessary to constantly draw power. Right? Considering that an always-on bulb is not always convert alternating current. It is right on.

Let the power of 4 watts bulb. Who consumes less energy?

motion detector only consume energy, but so much power that the wiring inside the light itself (the resistance of the motion sensor is equal to the resistance wire wiring lights - it draws only a few micro amps). the draw is the real power of the bulb.

4 Watts? This is nothing to light. Even then, the motion sensor draws very little.