Electrode - denkyoku (English spelling) electrode

A component that applies voltage, passes current, or extracts signals to vacuum, gas, liquid, solid, or living organisms. They are often plate- or rod-shaped metal or semiconductor. Examples include the plates of capacitors, the cathodes, grids, and anodes of vacuum tubes, the positive and negative electrodes of batteries, the positive and negative electrodes of electrolytic cells, and the electrodes of electrocardiographs. In batteries, the electrode with the higher potential is called the positive electrode, and the electrode with the lower potential is called the negative electrode. In electrolytic cells, the electrode on the side where a positive voltage is applied, i.e., the electrode where negative ions gather, is called the positive electrode, and the opposite electrode, i.e., the electrode where positive ions gather, is called the negative electrode. There are also transparent electrodes made of indium tin oxide (ITO), which are used in LCD panels, smartphone touch panels, electronic paper, solar cells, and organic electroluminescence (EL) panels. There are also glass electrodes, which use a thin film of special glass containing lithium ions to measure the potential inside the body.

[Madashi Fuse and Masazumi Yoshizawa]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

真空、気体、液体、固体などや生体に電圧を加えたり、電流を流したり、信号を取り出したりするための部品をいう。板状または棒状の金属または半導体が多い。たとえば、コンデンサーの極板、真空管のカソード、グリッド、アノード、電池の正極（陽極）や負極（陰極）、電解槽の正極や負極、心電計の電極などがある。電池では電位の高いほうの電極を正極、低いほうの電極を負極とよぶ。電解槽では正電圧を加える側の電極、すなわち陰イオンの集まる電極を正極、これと反対側の電極、すなわち陽イオンの集まる電極を負極とよぶ。また、酸化インジウムスズIndium Tin oxide（ITO）等による透明な電極もあり、液晶パネル、スマートフォンのタッチパネル、電子ペーパー、太陽電池や有機エレクトロルミネセンス（EL）パネル等に用いられている。リチウムイオンなどを含む特殊なガラスの薄膜を使って生体内の電位などを測るためのガラス電極とよばれるものもある。

［布施　正・吉澤昌純］

出典　小学館　日本大百科全書(ニッポニカ)日本大百科全書(ニッポニカ)について　情報 | 凡例