Westinghouse WL-341 Coolidge Tube

Ref. C7

As 20”(50 cm) long with a 4” (10 cm) bulb, this single focus tube dates probably to the mid or late thirties of the 20th century, and is typical of tubes of the “baby Coolidge type” of that period.

The cathode is of the line-focus type. The large tungsten target is embedded in a heavy copper anode. The target angle is about 12 degrees. The high tension connection is through the multi-layered metal radiator.

In  the wooden crating in which the tube was received, there was a document, printed January 1937, giving the following technical specifications :

• Effective focal spot : 4.2 mms
• Filament current range :3.5 – 4.9 Amps
• Fluoroscopy rating : 5 mA at 85 kV, 6.5 minutes.

View this chart of loads and maximum exposure times when the tube is used with either full rectification, half-wave rectification or without rectification (as self rectified), and whether the tube is hot or cold.