September 1965 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.
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Lots of old-time sci-fi movies and TV shows liked to display Lissajous patterns
on oscilloscopes when an authentic high tech look was needed in a scene. Every
engineer, technician, and physicist in the world - me included - roll his or her
eyes at the sight of such a lame attempt to impress the public. Of course the
truth is the first time I saw a Lissajous pattern gyrating on an o-scope screen,
I was mesmerized. The need to crank on the signal generator knobs and take
control of the electroluminescent object d'art was overwhelming. Now, in the same
manner that watching the first couple Space Shuttle launches was a thrill not to
be missed and then became just another launch, so, too, is watching a live
Lissajous pattern on a scope - it's just another Lissajous. Except, well, that's
not quite so - at least for me. I always eagerly viewed Shuttle launches and
landings (in the good old days when the U.S. had a manned space program), and I
still can't pass up the opportunity to play with Lissajous patterns on an
oscilloscope.
Unknown Frequency Quiz
By Robert P. Balin
An unknown frequency can be accurately determined by analyzing the Lissajous
pattern it forms when combined with a known frequency. Lissajous patterns can
quickly tell you the ratio of the frequencies applied to the vertical and horizontal
inputs of an oscilloscope. See if you can do problems 1-10. Ratios and unknown
frequencies are given on page 95.
(Hint) : In problem 1, for example, there are three-and-one-half vertical cycles as
indicated by the peaks at the top and bottom of the pattern, and two horizontal
cycles as indicated by the peaks on either side. This combination or vertical-to-horizontal
frequency ratio is 3.5 to 2, or 7 to 4. Therefore, if the vertical frequency
is 2800 cycles, the unknown horizontal frequency must be 1600 cycles to produce
the pattern shown.

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.
- 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
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- 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
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Quiz Answers
1) 7:4, 1600 cycles
2) 3:2, 750 cycles
3) 7:3, 600 cycles
4) 9:4, 540 cycles
5) 5:6, 1200 cycles
6) 4:5, 48 cycles
7) 7:6, 3600 cycles
8) 4:3, 160 cycles
9) 5:7, 4900 cycles
10) 8:3, 2400 cycles
Posted September 21, 2018
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