设万维读者为首页 广告服务 技术服务 联系我们 关于万维
简体 繁体 手机版
分类广告
版主:丁丁家长
万维读者网 > 海 二 代 > 帖子
How solar cells work?
送交者: jingchen 2019年02月15日05:42:50 于 [海 二 代] 发送悄悄话

How solar cells work?

First, we will look at hydro dams. Hydro dams are gigantic solar cells.

The sun shines on water. Some water molecules absorb photons and gain enough energy to jump out of water. They rise to the sky, fall down as rain, and some of them end up in a lake circled by the dam. Then water flows down the dam to generate electricity.

Solar cells are diodes. They contain PN junctions, which are energy dams.

The sun shines on solar cells. Some electrons absorb photons and gain enough energy to jump over the dam, or the PN junction. Then those high energy electrons flow over the wires to form electric currents, doing all kinds of works.

Semiconductors do all sorts of communication works. Solar cells generate electricity from light. LED generate light from electricity. All these devices are based on silicon. All are based on PN junction. 

In periodic table, silicon is in the same group of carbon, the backbone of life. It is right below carbon. In constructing PN junction, the P (positive) junction uses B, left to the group of carbon and silicon, the N (negative) junction uses P, right to the group of carbon and silicon. So B is in group three. Silicon is in group four. P is in group five. 



H







 Li

Be

B

C

N

O

F

Na

Mg

Al

Si

P

S

Cl


0%(0)
0%(0)
标 题 (必选项):
内 容 (选填项):
实用资讯
北美最全的折扣机票网站
贝佳药业美国专利【骨精华】消关节痛、骨刺、五十肩【心血通】改善心绞痛
一周点击热帖 更多>>
一周回复热帖
历史上的今天:回复热帖
2016: 别让孩子寒假过后变“笨”了
2015: 美国恶母10年杀死6名亲生婴儿
2015: 给孩子定多少规则才够