April 1967 Popular Electronics
Wax nostalgic about and learn from the history of early electronics. See articles
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
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)
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.
See answers below.
Popular Electronics published many quizzes over the years
- some really simple and others not so simple. Robert Balin created many of the quizzes.
This is a listing of all I have posted thus far.
Switching Quiz - October 1967
Angle Quiz - September 1967
Electronics Quiz - July 1967
- Bridge Circuit
Quiz -December 1966
- Diode Function
Quiz - August 1965
- Diagram Quiz, August
- TV Trouble Quiz,
- Electronics History Quiz,
- Scope-Trace Quiz,
Circuit Analogy Quiz, April 1973
Your Knowledge of Semiconductors, August 1972
- Ganged Switching
Quiz, April 1972
- Lamp Brightness
Quiz, January 1969
- Lissajous Pattern Quiz, September 1963
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
Quiz, September 1961
- RC Circuit
Quiz, June 1963
- Diode Quiz,
- Electronic Curves Quiz, February 1963
- Electronic Numbers Quiz, December 1962
- Energy Conversion Quiz, April 1963
Function Quiz, June 1962
- Unknown Frequency
Quiz - September 1965
Metals Quiz - October 1964
Measurement Quiz - August 1967
- Meter-Reading Quiz,
Geometry Quiz, January 1965
Factor Quiz, November 1966
Math Quiz, November 1965
- Series Circuit Quiz,
Electrochemistry Quiz, March 1966
- Electronic Analogy
Quiz, November 1961
Coupling Quiz, August 1973
- Electronics Analogy Quiz, August 1960
- Audio Quiz,
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
Function Quiz, January 1962
- Electronic Measurement Quiz, January 1963
Tube Quiz, February 1961
- Kool-Keeping Kwiz, June
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