# Graph Interpretation QuizApril 1967 Popular Electronics

 April 1967 Popular Electronics Table 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 is a quick test of your graph reading skills. It appeared in the April 1967 edition of Popular Electronics. I missed #6 - a temporary (hopefully) case of cranial rectumitis on my part. Maybe you will do better.

Graph Interpretation Quiz

By Robert P. Balin

Today's front-line electronic technician must be able to interpret readily the various charts and graphs devised by engineers to convey important information on the electrical characteristics of circuits as well as of individual components. In addition, the technician must be thoroughly familiar with the origin and composition of a variety of unusual as well as standard oscillographic waveforms. Test your ability to interpret the graphs and waveforms shown below (1-10) by selecting the most likely meaning, (A) or (B), from the two possibilities given in each case.

1.  The family of plate characteristic curves for a triode shows that as the plate voltage is increased the a.c. plate resistance (A) increases or (B) decreases.

2.  The distortion seen in this square-wave test signal indicates that the amplifier being tested is attenuating the (A) low frequencies or (B) high frequencies.

3.  The collector current vs. base current curve for a transistor indicates that as the base current is increased the beta (gain) of the transistor (A) increases or (B) decreases.

4.  This transmitter modulation pattern indicates that the r.f. carrier is (A) over-modulated or (B) under-modulated

5.  Output curves show that as a transistor's collector voltage increases, the a.c. output resistance (A) increases or (B) decreases.

6.  Vacuum-tube mutual transconductance curve indicates that as grid bias is increased mutual transconductance, Gm, (A) increases or (B) decreases.

7.  Of the two load lines, (A) and (B), shown in the graph at right, which one represents the larger value of load resistance?

8.  The magnetization curve for a transformer core material shows that as the core goes into saturation its permeability (A) increases or (B) decreases.

9.  The rate of change of a current depicted by a sine wave is greatest when the current is at its peak (A), or (B) when it is passing through 0.

10.  This frequency response curve for a tuned transformer indicates that the windings are (A) over-coupled or (B) under-coupled.

Popular Electronics published many quizzes over the years (as did a few other magazines to a lesser extent) - some really simple and others not so simple. Robert P. Balin created many of the quizzes. This is a listing of all I have posted thus far.

 Electronics Physics Quiz - March 1974 A Baffling Quiz - January 1968 Electronics IQ Quiz - May 1967 Plug and Jack Quiz - December 1967 Electronic Switching Quiz - October 1967 Electronic Angle Quiz - September 1967 International Electronics Quiz - July 1967 Bridge Circuit Quiz -December 1966 Diode Function Quiz - August 1965 Diagram Quiz, August 1966 TV Trouble Quiz, July 1966 Electronics History Quiz, December 1965 Scope-Trace Quiz, March 1965 Electronic Circuit Analogy Quiz, April 1973 Test Your Knowledge of Semiconductors, August 1972 Ganged Switching Quiz, April 1972 Lamp Brightness Quiz, January 1969 Lissajous Pattern Quiz, September 1963 Electronic Quizoo, October 1962 Electronic Photo Album Quiz, March 1963 Electronic Alphabet Quiz, May 1963 Quiz: Resistive? Inductive? or Capacitive?, October 1960 Vector-Circuit Matching Quiz, June 1970 Inductance Quiz, September 1961 RC Circuit Quiz, June 1963 Diode Quiz, July 1961 Electronic Curves Quiz, February 1963 Electronic Numbers Quiz, December 1962 Energy Conversion Quiz, April 1963 Coil Function Quiz, June 1962 "-Tron" Teasers Quiz - October 1963 Electronics World Polarity Quiz - March 1968 Amplifier Quiz Part I - February 1964 Semiconductor Quiz - February 1967 Unknown Frequency Quiz - September 1965 Electronics Metals Quiz - October 1964 Electronics Measurement Quiz - August 1967 Meter-Reading Quiz, June 1966 Electronic Geometry Quiz, January 1965 Electronic Factor Quiz, November 1966 Electronics Math Quiz, November 1965 Series Circuit Quiz, May 1966 Electrochemistry Quiz, March 1966 Electronic Analogy Quiz, November 1961 Electronic Coupling Quiz, August 1973 Electronics Analogy Quiz, August 1960 Audio Quiz, April 1955 Electronic Unit Quiz, May 1962 Capacitor Circuit Quiz, June 1968 Quiz on AC Circuit Theory, December 1970 Magnetic Phenomena Quiz, February 1962 Electronics Geography Quiz, April 1970 Electronic Menu Quiz, August 1963 Electronic Noise Quiz, August 1962 Electronic Current Quiz, October 1963 Electronic Inventors Quiz, November 1963 Resistor Function Quiz, January 1962 Electronic Measurement Quiz, January 1963 Vacuum Tube Quiz, February 1961 Kool-Keeping Kwiz, June 1970 Find the Brightest Bulb Quiz, April 1960

1 - B The slope of these curves represents the ratio Ip/Ep, or conductance (the reciprocal of resistance). As the plate voltage is increased, the slope and conductance also increase, and the resistance decreases.

2 - A The fundamental and low-frequency components of a square wave contribute chiefly to the center portion of its flat top. Thus, if an amplifier under test attenuates the low frequencies, a dip appears in the center of the square-wave test signal.

3 - B The slope of this curve represents the ratio lc/IB, or beta, the current gain of a transistor. As the base current increases, the slope of the curve and beta decrease.

4 - A Overmodulation can reduce an r.f. carrier to zero amplitude during a period of time as shown by the thin base line through the modulation envelope.

5 - A The slope of this family of curves indicates changes in the conductance of the transistor. As the collector voltage (VCE) is increased, the slope and conductance decrease, and the resistance increases.

6 - B The slope of this curve represents the ratio Ip/EG, or mutual conductance (Gm) of this vacuum tube. As the grid voltage (Eg) is increased, the slope and Gm decrease.

7 - B The slope of a load line represents the conductance of the load resistance. The load line with the lesser slope (B) shows a lower conductance, or higher resistance.

8 - B The slope of this curve reflects the ratio B/H, the permeability of the core material. As the curve goes over the knee, the slope and permeability both decrease.

9 - B At its peak amplitude, a sine wave changes from one finite value to another, but as it passes through zero it changes from a finite value to zero, resulting in an infinite percent change.

10 - A When the windings of a tuned air-core transformer are overcoupled, a dip is produced in the center of an otherwise single-peaked frequency-response curve, and two new resonant peaks occur at slightly higher and lower frequencies.

Posted July 26, 2012