EM34
The EM34 electron tube is a circular voting display, a so-called magic eye . It was installed in tube radios to make it easier to set the transmitter correctly. From around the mid-1950s, radio manufacturers relied on the more modern Noval types EM80, EM85 (magic fan) and EM84 (magic tape).
A special feature of this type is the asymmetrical light angle change introduced with the EM11 , which was implemented by different control triodes in the tube. Weak transmitters can just as easily be correctly tuned with the sensitive light angle as strong ones with the less sensitive ones.
The usually green luminous willemite layer appeared bluish or yellowish in some variants due to colored glasses or different manufacturing processes of the luminescent screen.
literature
- Werner Espe: Materials science of high vacuum technology . 3: auxiliary materials. VEB Deutscher Verlag der Wissenschaften, Berlin 1957.