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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This vector circuit matching
quiz will hurt the brain a little more than most of the ones that were printed in
Popular Electronics. In order to score well, it helps to visualize the circuits
relative to where they would appear on a Smith Chart. Capacitive impedances lie
in the bottom half and have negative phases (-s, -jω). Inductance lie in the
upper half and have positive phases (s, jω). The familiar 'ELI the ICE man' mnemonic
helps, too. Be sure to pay attention to the color of the vector arrow heads.
Example: In a purely inductive circuit like #4, voltage leads current by 90°.
Since phase rotation is CCW, you need to look for lettered phase diagram where the
white arrowhead (voltage) is 90° ahead of the black arrow head (current), going
in the CCW direction. Vector diagram letter 'H' looks like that. Circuit #10, being
purely capacitive, is just the opposite, so its vector diagram is...? Resistance
in parallel or series with reactance adjusts the phase angle somewhere between 0°
and 90° (not lying on an axis line). The rest are
combinations thereof.
Vector-Circuit Matching Quiz
By Robert P. Balin
Vector diagrams are widely used to show the magnitude and phase relationships
between voltages and currents in an a.c. circuit. A knowledge of vectors is a must
for understanding the theory behind frequency modulation and detection, color TV
and feedback circuits.
Ten circuits (1-10) are shown below; vector diagrams (A-J) representing the voltages
and currents in the circuits are also shown. To test your knowledge of vectors,
match the diagrams to the circuits. Note that this is a simple matching quiz - obviously
special cases might exist if the effects of resonance were considered. It is also
assumed that all elements are pure (that is, capacitors have only capacitance, inductors
only inductance, and resistors only resistance).
Standard counterclockwise vector rotation is used to indicate angles of lead
and lag. A white arrowhead represents a voltage vector; a
black arrowhead is a current vector. In all cases, the reference
is the line along the horizontal, extending to the right. Relative vectors are shown
for all voltages and currents in each circuit.
See answers below.
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.
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-
Elementary
Radio Quiz - December 1947 Radio-Craft
- Hi-Fi
Quiz - October 1955 Radio & Television News
- Electronics Physics
Quiz - March 1974 Popular Electronics
- A Baffling Quiz
- January 1968 Popular Electronics
- Electronics IQ
Quiz - May 1967 Popular Electronics
- Plug and Jack
Quiz - December 1967 Popular Electronics
- Electronic
Switching Quiz - October 1967 Popular Electronics
- Electronic
Angle Quiz - September 1967 Popular Electronics
- International
Electronics Quiz - July 1967 Popular Electronics
- FM Radio
Quiz - April 1950 Radio & Television News
- Bridge Circuit
Quiz -December 1966 Popular Electronics
- Diode Function
Quiz - August 1965 Popular Electronics
- Diagram Quiz,
August 1966 Popular Electronics
- Quist Quiz - November
1953 QST
- TV Trouble Quiz,
July 1966 Popular Electronics
- Electronics History Quiz,
December 1965 Popular Electronics
- Scope-Trace Quiz,
March 1965 Popular Electronics
-
Electronic
Circuit Analogy Quiz, April 1973
-
Test Your Knowledge of Semiconductors, August 1972 Popular Electronics
- Ganged Switching
Quiz, April 1972 Popular Electronics
- Lamp Brightness
Quiz, January 1969 Popular Electronics
- Lissajous Pattern Quiz, September 1963 Popular Electronics
- Electronic
Quizoo, October 1962 Popular Electronics
- Electronic Photo Album Quiz, March 1963 Popular Electronics
- Electronic Alphabet Quiz, May 1963 Popular Electronics
- Quiz: Resistive?
Inductive? or Capacitive?, October 1960 Popular Electronics
- Vector-Circuit Matching Quiz, June 1970 Popular Electronics
- Inductance
Quiz, September 1961 Popular Electronics
- RC Circuit Quiz,
June 1963 Popular Electronics
- Diode Quiz, July
1961 Popular Electronics
- Electronic Curves Quiz, February 1963 Popular Electronics
- Electronic Numbers Quiz, December 1962 Popular Electronics
- Energy Conversion Quiz, April 1963 Popular Electronics
- Coil Function
Quiz, June 1962 Popular Electronics
-
Co-Inventors Quiz - January 1965 Electronics World
-
"-Tron" Teasers Quiz - October 1963 Electronics World
- Polarity Quiz
- March 1968 Popular Electronics
-
Television
I.Q. Quiz - October 1948 Radio & Television News
- Amplifier Quiz
Part I - February 1964 Popular Electronics
- Semiconductor
Quiz - February 1967 Popular Electronics
- Unknown
Frequency Quiz - September 1965 Popular Electronics
- Electronics
Metals Quiz - October 1964 Popular Electronics
- Electronics
Measurement Quiz - August 1967 Popular Electronics
- Meter-Reading
Quiz, June 1966 Popular Electronics
- Electronic
Geometry Quiz, January 1965 Popular Electronics
- Electronic
Factor Quiz, November 1966 Popular Electronics
- Electronics
Math Quiz, November 1965 Popular Electronics
- Series Circuit
Quiz, May 1966 Popular Electronics
- Electrochemistry
Quiz, March 1966 Popular Electronics
- Biz
Quiz: Test Your Sales Ability - April 1947 Radio News
- Electronic
Analogy Quiz, November 1961 Popular Electronics
- Electronic
Coupling Quiz, August 1973 Popular Electronics
- Electronics Analogy Quiz, August 1960 Popular Electronics
- Audio Quiz, April
1955 Popular Electronics
- Electronic Unit
Quiz, May 1962 Popular Electronics
- Capacitor
Circuit Quiz, June 1968 Popular Electronics
- Quiz on AC Circuit Theory, December 1970 Popular Electronics
- Magnetic Phenomena Quiz, February 1962 Popular Electronics
- Electronics Geography Quiz, April 1970 Popular Electronics
- Electronic
Menu Quiz, August 1963 Popular Electronics
- Electronic Noise Quiz, August 1962 Popular Electronics
- Electronic Current Quiz, October 1963 Popular Electronics
- Electronic Inventors Quiz, November 1963 Popular Electronics
- Resistor Function
Quiz, January 1962 Popular Electronics
- Electronic Measurement Quiz, January 1963 Popular Electronics
- Vacuum Tube Quiz,
February 1961 Popular Electronics
- Kool-Keeping Kwiz, June
1970 Popular Electronics
- Find the Brightest
Bulb Quiz, April 1960 Popular Electronics
-
Where Do the Scientists Belong? - Feb 19, 1949 Saturday Evening
Post
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Vector-Circuit Quiz Answers
1-B In a series circuit containing only resistance, the current is in phase with
the applied voltage.
2-F In a parallel circuit, there are three currents and a single voltage, which
is used as the reference vector (directed horizontally to the right). The current
in an inductor lags the voltage across the inductor by 90 degrees. The current into
a capacitor leads the voltage across the capacitor by 90 degrees. The total circuit
current is the difference between the branch currents.
3-J The current is used as the reference vector. The voltage drops across the
capacitor and resistor add vectorially to equal the applied voltage.
4-H The applied voltage is the reference vector. The current in the circuit lags
the voltage by 90 degrees.
5-G The applied voltage is the reference vector. The two branch currents add
vectorially to equal the circuit current.
6-A The current is used as the reference vector. The voltage drops across the
resistor and inductor add vectorially to equal the applied voltage.
7-I The current is the reference vector. The voltage drops across the inductor
and capacitor are 180 degrees out of phase, and the difference between them is equal
to the applied voltage.
8-E The applied voltage is the reference. The leading currents in each branch
are in phase and add to equal total circuit current.
9-D The applied voltage is the reference. The two branch currents add vectorially
to equal total circuit current.
10-C The applied voltage is the reference. The current in the inductor leads
the applied voltage by 90 degrees.
Posted March 22, 2019(original June 4, 2014)
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