Amplifier Quiz
February 1964 Popular Electronics

February 1964 Popular Electronics

February 1964 Popular Electronics Cover - RF CafeTable of Contents

Wax nostalgic about and learn from the history of early electronics. See articles from Popular Electronics, published October 1954 - April 1985. All copyrights are hereby acknowledged.

Here be another brain teaser from quizmaster Robert P. Balin. The "Amplifier Quiz" is one of sixty or so I have posted thus far from vintage issues of Popular Electronics magazine. Having been created in 1964, the circuit schematics use vacuum tubes, but don't let that inhibit you from taking the test. Enhancement mode field effect transistors (FETs) are an apt analogy to tubes for determining function, so I added symbols for FETs next to the vacuum tube symbols to help you visualize the equivalence. I usually do a respectable job on these quizzes, but have to admit to only getting 4 out of 6 this time (67%), and one of those was just a lucky, semi-educated guess. Shameful.

Amplifier Quiz Part I


By Robert P. Balin

Over the years-many types of vacuum tube amplifiers have been devised for specific uses. Here are six that range from easy to tough in difficulty of recognition. Try your hand at matching up the circuits (A-F) shown with the names (1-6) commonly given them in electronics handbooks. Even old-timers may have trouble recognizing all six without guesswork. Next month Part " will offer six transistor circuits to tax your memory.


1 Cascade amplifier ____


2 Cathode follower amplifier ____


3 Direct current amplifier ____


4 Video amplifier ____


5 Differential amplifier ____


6 Doherty amplifier ____



Quizzes from vintage electronics magazines such as Popular Electronics, Electronics-World, QST, and Radio News were published over the years - some really simple and others not so simple. Robert P. Balin created most of the quizzes for Popular Electronics. This is a listing of all I have posted thus far.

RF Cafe Quizzes

Vintage Electronics Magazine Quizzes

Vintage Electronics Magazine Quizzes







Amplifier Quiz Answers

1 - C   The Cascode amplifier uses one triode as a grounded-cathode amplifier driving the cathode of a second triode in a grounded-grid circuit. It has the good signal-noise ratio of a triode, and the gain of a pentode.

2 - E   A Cathode Follower amplifier has very high input impedance, low output impedance, and provides power gain, but a voltage loss.

3 - B   A Direct Current amplifier is direct-coupled (uses no coupling capacitors), and can amplify a change of the d.c. voltage between its input grid and cathode.

4 - A   The Video amplifier is broad banded by means of a complex network in its plate circuit, to pass the entire band of video frequencies to the cathode of the TV picture tube,

5 - F   A Differential amplifier has two inputs, and provides a single output proportional to the difference between the two input signals.

6 - D   The Doherty amplifier used in some fixed-frequency broadcast transmitters employs one tube to provide normal carrier level output, and a second tube for the added carrier output needed to transmit the positive peaks of the modulation wave.




Posted January 30, 2020