23624 Radio Tube Fundamentals, By George J. Christ.
This book is a faithful reprint of the Gersmack Library No. 45 book published in 1951. This not just another tube substitution guide or book of pin-out voltages. This book delves deeply into the theory and science of the vacuum tube. It explores the physical aspects of each element within the tube. It even covers photo tubes and indicator tubes. ©1951 Lindsay 96 pages.