O'Reilly logo

Valve Radio and Audio Repair Handbook by CHAS MILLER

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Chapter 6

What you need to know about valves (1)

The simplest kind of valve, and the one that inspired the name, is the two-electrode type or diode (from the Greek dis, twice + electrode). In essence this consists of a filament, not unlike that of an electric lamp, around which is mounted a metal plate in the form of a cylinder or flat box, the whole being sealed into a glass bulb and evacuated. When the filament is lighted by means of a battery or a source of low voltage AC it emits negatively charged particles of electricity called electrons. If another battery of, say, about 30 V is connected with its negative terminal to one side of the filament and its positive to the metal plate a current will pass between them; however, if the battery connections ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required