C877

This tube was used in dry cell radios and was developed by General Electric in 1925. It had a short commercial life and was discontinued in 1929. The tube resembled an automotive light bulb and was connected between two of the 45 volt B batteries. It was used to protect filaments of the UV199 tubes in case of a short circuit with the battery wiring. The base was double contact Ba15D. The main use of the tube was in the RCA Radiola 25 receiver, where it was used as a current limiter at the junction of two 45 volt batteries.