The 17Z3 is an efficiency diode for television line scan and the design dates to the early 1950s. This was a popular design and was made by many companies under various Type designations. This Cossor example has green paint whereas our other Cossor 17Z3 has brown paint that may possibly have been green before it was heated.
The rectifier is specified as having a peak inverse voltage rating of 4,500 Volts, and a peak current rating of 450 mA.
The anode is oped out at the ends to offer a greater heat radiating area.
The stitched anode seen full face. The cathode connects to the top cap.
The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 72 mm tall.