Kỹ thuật năng lượng mặt trời hoạt động bao gồm việc sử dụng các tấm quang điện và năng lượng mặt trời nhiệt thu để khai thác năng lượng. | Solar Power 67 Chap. 2. The gravitational analogy would be a pin ball machine with two levels and a ramp where they join up. At the upper level N-side there are pins and a number of energetic balls reverberating around. On the lower P-side there is a similar number of pins a few holes just large enough for balls to fall into and far fewer pin balls than on the upper level. On a flat table by dint of fortuitous collisions in the upper tier a pin ball may occasionally head towards the ramp and drop to the lower layer. Some of these will disappear into holes but those that do not and continue to bounce around on the lower layer will not get back to the upper layer because of the ramp. At this point the analogy only partially describes the semi-conductor diode action because there is nothing to stop the rattling pin balls on the upper level continuing to reach the lower level. This can be corrected by introducing a gravitational field to model the electric field in the diode. We need to imagine that balls falling into the holes trigger a mechanism that tilts the table raising the lower end and lowering the upper end until the point is reached where pin balls heading for the ramp are turned back by the slope of the table . by the force of gravity. The wave detection analogy is almost complete. Consider finally what happens if the table is rocked very gently about this stable state. Increasing the tilt will have virtually no effect on ball movement down the ramp with the increased gravitational force further discouraging even the most energetic balls from approaching the ramp. It is assumed that the tilt is never enough to allow balls to roll up the ramp. On the half cycle of the rocking movement when the tilt is reduced towards zero we return to a state where gravity is again insufficient to prevent some balls on the upper level finding their way over the ramp. Thus the oscillating movement results in a one way current of balls DC when averaged on the tilt .
