This is the schematic symbol of an old radio tube from the 1940´s. It´s the UCH4 Triode-heptode. heptode triode radio tube uch4 Radio Tube UCH4
This is the schematic symbol of an old radio tube from the 1940ôs. Itôs the UCH4 Triode-heptode electronic heptode radio tube uch4 Radio Tube UCH4