1996 - 2016
BSEE - KB3UON
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The Internet was still largely an unknown entity at the time and not much was available in the form of WYSIWYG ...
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All RF Cafe quizzes would make perfect fodder for employment interviews for technicians or engineers - particularly those who are fresh out of school or are relatively new to the work world. Come to think of it, they would make equally excellent study material for the same persons who are going to be interviewed for a job.
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Note: Many answers contain passages quoted in whole or in part from the text.
This quiz is based on the information presented in Make Your Own Tube Testers and Electron Tube Equipment, by Gary Steinbaugh.
With more than 30 years of RF engineering experience and Ham radio involvement, Gary has a very broad and deep proficiency in electronics. His new book, Make Your Own Tube Testers and Electron Tube Equipment, is a great assimilation of his personal knowledge and includes some of the highest quality line drawings and photographs of any technical book I have ever seen - and I've seen a lot of them! The preface section is also unique in nature, followed by a short history of and basic circuit design principles for vacuum tubes. Gary also conceived of and built a 3-dimensional physical model of the plate, transfer, and constant current characteristic curves for a typical vacuum tube (6SN7); you've never seen this before. The homebrew tube tester and power supply projects described in the text and built by Gary are exceptional examples of craftsmanship.
1. Which of the following are negative properties of vacuum tubes?
Heavy and bulky
b) Electrically fragile (intolerant of overloads and spikes)
c) Low power efficiency
d) Capacitance varies with applied voltage
2. Which of the following are negative properties of transistors?
a) Mechanically fragile (impact and vibration)
b) High output impedance requiring matching transformers
c) Low impedance requiring high-value capacitors for coupling
d) Tend toward high distortion
a) Nikola Tesla
b) Lee de Forest
c) Thomas Edison
d) George Westinghouse
4. What is a "bogey" vacuum tube?
a) A normal, or "typical," tube statistically centered in the distribution
of datasheet specifications.
b) A bad tube
c) A tube that measured one above par
d) A tube used for destructive testing
5. What is the most common type of gradual failure in a vacuum tube?
a) Glass envelope breakage
b) Filament breakage
c) Pin bending
d) Low cathode emission (aka cathode depletion)
6. What are the two basic types of serviceman's vacuum tube testers?
a) High voltage and low voltage
b) Cathode emission measurement only, and both cathode emission and amplification measurements
c) Standard tube size and peanut tube size
d) Hand carried and backpack carried
7. What is a typical vacuum tube filament temperature?
a) 400° C (752° F)
b) 800° C (1,472° F)
c) 1,200° C (2,192° F)
d) 1,600° C (2,912° F)
8. What is a sesquimultiplier?
a) A sesquine duplicator
b) An ancient form of the abacus
c) A vacuum tube circuit that performs numerical multiplication
d) A circuit that multiplies voltage by 1.5
9. Why are "operational amplifiers" (aka "opamps") named thus?
a) They were originally part of circuits for performing mathematical operations
b) They were developed for use in medical equipment
c) They were first used in audio equipment for opera houses
d) They were named after the Greek philosopher Operatus Amplifcatius
10. What is the word used to the measure of how significant the space charge effect is on the beam's motion ?
Need some help? Click here for the answers and explanations.
Posted January 1, 2014