This site uses third-party website tracking technologies to provide and continually improve our services, and to display advertisements according to users' interests. I agree and may revoke or change my consent at any time with effect for the future.
 TT21
BEAM TETRODES TT22
ISSUE 1
Beam tetrodes with oxide coated cathodes, the TT21 and TT22 are identical except for their heater ratings. They are designed for use as r.f. power amplifiers