The pentode was superior to a triode as an output valve; it could deliver much more power to the load for the same plate supply and required considerably less drive. This type could produce over 5 watts when run from a 400 volt supply. 4.0 volt directly heated cathode.

The power pentode was developed by Bernard Tellegen of Philips in 1927. The first type made was the B443. The E443N was released in 1928.

Physical Description

Internal structure of a directly heated pentode valve with horizontal elements. American style 5 pin (UY) base mounted on display block with an intact example of the same type of valve (ST 021546).

More Information