by Jerry Sevick, W2FMI
This tutorial introduces the theory and practice of transmission line transformers (TLT). The TLT, which was first introduced by Guanella in 1944, was meant to match the high impedance of a 960-ohm push-pull vacuum tube amplifier to the low impedance of a 60-ohm coaxial cable in the high-frequencyband. Although Guanella's objective could never be realized, his goal remains useful today. With the advent of the transistor, the TLT can be applied to matching low impedances to coaxial cable of up to 50 ohms. Understanding transmission line theory is a prerequisite to understanding TLTs because they transmit energy from input to output by a transmission mode. In an innovative approach to the subject, Sevick divides TLTs into four classes: TLTs with ratios of 1:1, 1:4, less than 1:4 and greater than 1:4. The first two sections in this course cover 1:1 baluns and 1:4 baluns and ununs, as discussed by Guanella and Ruthroff. Additional sections review TLTs with ratios less than 1:4 and greater than 1:4, such as 1:6, 1:9, 1:12. The course concludes with a discussion of information on diode mixers and power combiners\splitters.
The material covered in this course provides incentive to investigate:
This course allows you to move through each session at your own speed and requires no extra work books.
Windows 95/98/2000/NT/XP or higher
Pentium II 333 MHz or faster
64 MB of available RAM (128 MB recommended)
Navigation is similar to any computer-based information application. Clearly designated sections with an intuitive layout leave no frustrating distractions.
1) The CD-ROM can be started from any PC that has Windows 95 (or higher), at least 64 MB of RAM, a sound card and speakers.
2) The material may be accessed by either choosing to view the course start to finish, or by choosing individual pages of interest.
3) Once the course is started, no interaction is required. The course can be paused at any point, and can be viewed page by page like a book.
TABLE OF CONTENTS
Sevick's classic Transmissions Line Transformers. Now in its fourth edition, this title remains the definitive text on TLTs for higher requencies.
CD-ROM. Course material and instruction by Jerry Sevick. © 2002, by SciTech Publishing.