August 1961 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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Robert Balin, Popular
Electronics magazine's quizmeister, created this CapaciQuiz for the February
1961 issue. Most of these are elementary, but think carefully about the exact
wording of Q4 before you answer. With Q8, believe the better explanation is that
for a purely capacitive circuit, current and voltage are 90° out of phase, so when the sinewave voltage is at zero, the current is at a maximum.
Note that Q6 and Q10 are opposites (parallel vs. series capacitor combinations),
so if you have trouble reasoning one of the configurations, work on the other
and then you'll know both. Bon chance!
CapaciQuiz Quiz
By Robert P. Balin
No one can really understand electronics what factors determine capacitance and
really works. How many of the questions illustrated below can you answer correctly?
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1) When charged, the smallest of the two capacitors shown at left
will have the largest voltage across it.
TRUE FALSE
2) The tuning capacitor will be wide open when you tune in a radio
station on the low end of the band.
TRUE FALSE
3) The total capacitance of the two capacitors in series is always
less than that of the smallest one.
TRUE FALSE
4) The lamp in this circuit will light because the capacitor can
pass a.c. current.
TRUE FALSE
5) A small capacitor cannot be charged to as high a voltage as a
large capacitor.
TRUE FALSE
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6) Because it is connected in parallel with the main tuning capacitor,
a trimmer has its greatest effect at the high end of the band.
TRUE FALSE
7) Tightening the adjusting screw on a compression-type capacitor
will decrease its capacitance.
TRUE FALSE
8) The current (I) into the capacitor is at its maximum when the
sine-wave voltage (E) is practically zero.
TRUE FALSE
9) Because it is in series with the main tuning capacitor, a padder
has its greatest effect at the low end of the band.
TRUE FALSE
10) The voltage (E) across the capacitor increases as the frequency
of the source voltage is increased.
TRUE FALSE
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See answers below.
Quizzes from vintage electronics magazines such as Popular
Electronics, Electronics-World, QST,
Radio-Electronics, 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 Quiz #71:
Tech Headlines for Week of 3/13/2023
- RF Cafe Quiz #70:
Analog &
RF Filter Basics
- RF Cafe Quiz #69:
RF
Electronics Basics
- RF Cafe Quiz #68:
RF & Analog Company Mergers & Acquisitions in 2017
- RF Cafe Quiz #67:
RF & Microwave Company Name Change History
- RF Cafe Quiz #66:
Spectrum and Network Measurements
- RF Cafe Quiz #65:
Troubleshooting & Repairing Commercial Electrical Equipment
- RF Cafe Quiz #64:
Space-Time Adaptive Processing for Radar
- RF Cafe Quiz #63:
Envelope Tracking Power Amplifiers
- RF Cafe Quiz #62:
Stimson's Introduction to Airborne Radar
- RF Cafe Quiz #61:
Practical Microwave Circuits
- RF Cafe Quiz #60:
Ten Essential Skills for Electrical Engineers
- RF Cafe Quiz #59:
Microwave Circulator Design
- RF Cafe Quiz #58:
Microwave and Millimeter-Wave Electronic Packaging
- RF Cafe Quiz #57:
Frequency-Agile Antennas for Wireless Communications
- RF Cafe Quiz #56:
Tube Testers
and Electron Tube Equipment
- RF Cafe Quiz #55:
Conquer
Radio Frequency
- RF Cafe Quiz #54:
Microwave Mixer Technology and Applications
- RF Cafe Quiz #53:
Chipless RFID Reader Architecture
- RF Cafe Quiz #52:
RF and Microwave Power Amplifiers
- RF Cafe Quiz #51:
Antennas and Site Engineering for Mobile Radio Networks
- RF Cafe Quiz #50:
Microstrip Lines and Slotlines
- RF Cafe Quiz #49:
High-Frequency Integrated Circuits
- RF Cafe Quiz #48:
Introduction to Infrared and Electro-Optical Systems
- RF Cafe Quiz #47:
LCP for Microwave Packages and Modules
- RF Cafe Quiz #46:
RF, Microwave, and Millimeter-Wave Components
- RF Cafe Quiz #45:
Dielectric and Thermal Properties of Materials at Microwave Frequencies
- RF Cafe Quiz #44:
Monopulse Principles and Techniques
- RF Cafe Quiz #43:
Plasma Antennas
- RF Cafe Quiz #42: The Micro-Doppler
Effect in Radar
- RF Cafe Quiz #41: Introduction
to RF Design Using EM Simulators
- RF Cafe Quiz #40: Introduction
to Antenna Analysis Using EM Simulation
- RF Cafe Quiz #39: Emerging
Wireless Technologies and the Future Mobile Internet
- RF Cafe Quiz #38: Klystrons,
Traveling Wave Tubes, Magnetrons, Crossed-Field Amplifiers, and Gyrotrons
- RF Cafe Quiz #37: Component
Reliability for Electronic Systems
- RF Cafe Quiz #36: Advanced
RF MEMS
- RF Cafe Quiz #35: Frequency
Synthesizers: Concept to Product
- RF Cafe Quiz #34: Multi-Gigabit
Microwave and Millimeter-Wave Wireless Communications
- RF Cafe Quiz #33: Battlespace
Technologies: Network-Enabled Information Dominance
- RF Cafe Quiz #32: Modern Communications
Receiver Design and Technology
- RF Cafe Quiz #31: Quantum
Mechanics of Nanostructures
- RF Cafe Quiz #30: OFDMA System
Analysis and Design
- RF Cafe Quiz #29: Cognitive
Radar
- RF Cafe Quiz #28: Human-Centered
Information Fusion
- RF Cafe Quiz #27: Remarkable
Engineers
- RF Cafe Quiz #26: Substrate
Noise Coupling in Analog/RF Circuits
- RF Cafe Quiz #25: Component
Reliability for Electronic Systems
- RF Cafe Quiz #24: Ultra Low
Power Bioelectronics
- RF Cafe Quiz #23: Digital
Communications Basics
- RF Cafe Quiz #22: Remember
the Basics?
- RF Cafe Quiz #21: Wireless
Standards Knowledge
- RF Cafe Quiz #20: Famous First
Names
- RF Cafe Quiz #19: Basic Circuit
Theory
- RF Cafe Quiz #18: Archaic
Scientific Words & Definitions
- RF Cafe Quiz #17: Inventors &
Their Inventions
- RF Cafe Quiz #16: Antennas
- RF Cafe Quiz #15: Numerical
Constants
- RF Cafe Quiz #14: Oscillators
- RF Cafe Quiz #13: General
Knowledge
- RF Cafe Quiz #12: Electronics
Corporations Headquarters
- RF Cafe Quiz #11: Famous Inventors &
Scientists
- RF Cafe Quiz #10: A Sampling
of RF & Wireless Topics
- RF Cafe Quiz #9: A Smorgasbord
of RF Topics
- RF Cafe Quiz #8: Hallmark Decades
in Electronics
- RF Cafe Quiz #7: Radar Fundamentals
- RF Cafe Quiz #6: Wireless Communications
Fundamentals
- RF Cafe Quiz #5: Company Logo
Recognition
- RF Cafe Quiz #4: General RF
Topics
- RF Cafe Quiz #3: General RF/Microwave
Topics
- RF Cafe Quiz #2: General RF
Topics
- RF Cafe Quiz #1: General RF
Knowledge
- 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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-
What's
Your EQ? - January 1962 Radio-Electronics
-
What's
Your EQ? - February 1962 Radio-Electronics
-
What's
Your EQ? - March 1962 Radio-Electronics
-
What's
Your EQ? - July 1961 Radio-Electronics
-
What's
Your EQ? - August 1961 Radio-Electronics
-
Can You
Name These Strange Electronic Effects? - August 1962 Radio-Electronics
-
What's
Your EQ? - September 1961 Radio-Electronics
-
What's
Your EQ? - September 1962 Radio-Electronics
-
What's Your EQ? - October 1961 Radio-Electronics
-
What's Your EQ? - November 1961 Radio-Electronics
-
What's Your EQ? - March 1964 Radio-Electronics
-
What's Your EQ? - April 1962 Radio-Electronics
-
What's Your EQ? - May 1962 Radio-Electronics
-
What's Your EQ? - June 1962 Radio-Electronics
-
What's Your EQ? - April 1967 Radio-Electronics
-
What's Your EQ? - March 1967 Radio-Electronics
-
What's Your EQ? - December 1964 Radio-Electronics
-
What's Your EQ? - January 1967 Radio-Electronics
-
Wanted: 50,000 Engineers - January 1953 Popular Mechanics
-
What's Your EQ? - August 1964 Radio-Electronics
- Voltage Quiz
- December 1961 Popular Electronics
-
What is It? - June 1941 Popular Science
- What Do You Know
About Resistors? - April 1974 Popular Electronics
-
What's Your EQ? - September 1963 Radio-Electronics
- Potentiometer Quiz - September
1962 Popular Electronics
-
Mathematical Bafflers - March 1965 Mechanix Illustrated
- Op Amp Quiz -
October 1968 Popular Electronics
- Electronic "A"
Quiz - April 1968 Popular Electronics
-
What's Your EQ? - May 1961 Radio-Electronics
-
Popular Science Question Bee - February 1939 Popular Science
-
What is It? - A Question Bee in Photographs - June 1941 Popular Science
-
What's Your EQ? - June 1961 Radio-Electronics
-
What's Your EQ? - June 1964 Radio-Electronics
-
What's Your EQ? - May 1964 Radio-Electronics
-
What's Your EQ? - August 1963 Radio-Electronics
-
What's Your EQ? - May 1963 Radio-Electronics
- Bridge
Function Quiz - September 1969 Radio-Electronics
-
What's Your EQ? - March 1963 Radio-Electronics
-
What's Your EQ? - February 1967 Radio-Electronics
-
Circuit Quiz - June 1966 Radio-Electronics
-
What's Your EQ? - June 1966 Radio-Electronics
- Electronics
Mathematics Quiz - June 1969 Popular Electronics
- Brightest
Light Quiz - April 1964 Popular Electronics
-
What's Your EQ? - April 1963 Radio-Electronics
- Electronics "B" Quiz
- July 1969 Popular Electronics
- Ohm's Law Quiz
- March 1969 Popular Electronics
-
Antenna Quiz - November 1962 Electronics World
- Color Code Quiz
- November 1967 Popular Electronics
- CapaciQuiz
- August 1961 Popular Electronics
- Transformer
Winding Quiz - December 1964 Popular Electronics
-
Audiophile Quiz - November 1957 Radio-electronics
- Capacitor
Function Quiz - March 1962 Popular Electronics
- Greek Alphabet
Quiz - December 1963 Popular Electronics
- Circuit
Designer's Name Quiz - July 1968 Popular Electronics
-
Sawtooth Sticklers Quiz - November 1960 Radio-Electronics
-
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
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Vacuum Tube Quiz Answers
1) True. The voltage to which a capacitor is charged depends
upon the density of the electrons on one of its plates. A given number of electrons
on a small plate will result in a higher charge density and therefore a higher voltage
than the same number of electrons on a larger plate.
2) False. When a tuning capacitor is wide open, there is a minimum
of plate area in use and the effective capacitance is therefore at a minimum. The
smaller the capacitance in parallel with a given inductance, the higher will be
the resonant frequency of the circuit.
3) True. Capacitance varies inversely - but not linearly - with
the distance between plates. Putting capacitors with different -sized plates in
series not only increases the separation between the outermost plates but also reduces
the effective plate area to that of the smallest one.
4) False. The plates of a capacitor are separated by a dielectric
material which, being an insulator, prevents the capacitor from passing either a,c,
or d.c. current. But the movement of electrons on and off the plates is an effective
a.c. current to the lamp, and the lamp lights accordingly.
5) False. A capacitor can be charged to any voltage that does
not exceed the breakdown voltage of the dielectric material between its plates.
The type of dielectric and its thickness determine the working voltage of a capacitor.
6) True. As the capacitance of a trimmer is small in comparison
with that of the main tuning capacitor, during most of the latter's tunable range
the trimmer will add little to the total capacitance in use. But at the high end
of the band where the main tuning capacitance is at a minimum, the trimmer contributes
a larger percentage of the capacity in use.
7) False. Tightening the adjusting screw presses the mica dielectric
and metal plates closer together. The thickness of the air dielectric which is also
present is thus reduced and the capacitance is thereby increased.
8) True. Even when the voltage present is little more than zero
a large current flows as the capacitor is being charged. At any later time, the
voltage built up on the capacitor limits the circuit current to successively smaller
values.
9) True. A padder decreases the effective capacitance across
the inductance and thus helps in the alignment of an oscillator at the low end of
the band. Since it is relatively large, the padder will have increasingly less influence
as the capacitance of the main tuning capacitor is decreased.
10) False. As the frequency of the source voltage is increased,
there is less time for the electrons to flow on or off the plates. The voltage to
which the capacitor can charge therefore decreases.
Posted August 17, 2022
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