Sensibly equivalent¶ to:
A4100 H4100 KL1/ACR REN804
This exhibit from Philips has a woven mesh anode and an indirectly heated tubular cathode with an oxide coating. The almost square section grid is 2.8 mm across the broad face and the anode is about 6 mm across the face. The construction features a glass tube support mounted horizontally at the top of the anode to give extra rigidity to the electrodes. This stability would help reduce microphony.
The top of the envelope has etched identification lettering. In addition to the makers name and the trade name 'Miniwatt' the country of origin is marked as Made in Holland.
The balloon envelope is 46 mm in diameter, and excluding the B5 base pins is 86 mm tall.
References: Datasheet & 3002. Type E415 was first introduced in 1927.
Absolute Maximum Operating Conditions¶
Updated February 07, 2013. shape:balloon construction:pinch type:triode age:1920.1930 base:b5 heater:4.0v pins:4 pin:1.a pin:2.g1 pin:3.h pin:4.h pin:5.k