Amrad S-3000
Half Wave Rectifier
1922

The S-3000 was the first cold cathode gas (helium) rectifier on the market and used the "short-path" design to obtain rectification. These tubes were intended for use by amatuers in transmitting equipment. The tube was rated for 50 mA output and 400 volt input. This tube has been seen with an Amrad label marked Code 2846.