Transistor Museum Early Germanium Power Transistor History by Joe Knight Tung-Sol

A SURVEY OF EARLY POWER TRANSISTORS

by Joe A. Knight

TUNG-SOL 1950s/60s GERMANIUM

POWER TRANSISTORS

If Tung-Sol Electric were still in business today they would be over 100 years old. Starting around 1904 they began producing electric lamps for the newfangled contraption called the 'horse-less carriage' and went on to manufacture vacuum tubes in the 1930's through the 1970's. Second only to RCA, Tung-Sol had the widest product line of vacuum tubes ever made. In the 1950's, their research lab produced some of the most successful audio tubes still sought after today, the 5881 and the 6550 pentodes. Likely very occupied with their successful tube production, when the move towards semiconductors began Tung-Sol seemed slow to get aboard. Not wanting to rush to market like most everyone else, it wasn't until 1954 that they released their first transistor line, the scarce "DR-1XX" series. Sometime later in 1954 they released a 5-watt output device called the "DR-150". Little is known about these first devices as few apparently made it into circulation. The following "Engineering Sample" may well give us some idea of where their thinking was in that developmental period of 1953/1954.

This above Tung-Sol Power Transistor ("TP-13X" ? - not sure as some of the paint is missing) is similar to the oversize device Germanium Products was developing (see the GPC chapter, page 2, far right) in late 1953. (Yes, the above element leads are broken from the germanium junction). A newer RCA TO-5 transistor is shown for size comparison. Remember, at this time, circa 1953, achieving a 1+ watt dissipation level was a major undertaking. The size of this device and the heavy leads may well have given Tung-Sol a satisfactory output level such that the 5-watt DR-150 was attainable by late 1954.

Using an in-house numbering system may have made it difficult for users to compare the Tung-Sol products to other RETMA registered 2NXX devices. In 1955, Tung-Sol came out with another round of hard-to-find in-house numbered small transistors called the "TS-16X" series. These may have been the first of the "Baby-Blue" (color) types that Tung-Sol was identified with for so many years. There were no Power Transistor devices announced in this new series.

Go To Tung-Sol Early Power Transistors, Page 2

Joe A. Knight Early Power Transistor History – TUNG-SOL