September 1963 Radio-Electronics
[Table of Contents]
Wax nostalgic about and learn from the history of early electronics.
See articles from Radio-Electronics,
published 1930-1988. All copyrights hereby acknowledged.
|
Three new circuits challenges
await you from this "What's Your EQ?" feature in the September 1963 issue of
Radio-Electronics magazine. "EQ," by the way, stands for Electronics Quotient
(a la "IQ"). The first one is a relatively simple solving of two equations in two
unknowns. Yes, I worked it out; in fact, my solution is via the "complete the square"
method, whereas the author's solution plugs the coefficients in the quadratic equation.
"Why No Voltage" is not too hard, and is easily understood based on the author's
explanation. "Where's the TVI?" is more of a case study of an actual experience
in locating the source of television interference. The culprit ends up being similar
to the source of
AM radio interference I got on my car radio in a certain area on my drive to
work. It was worst on high humidity mornings. Turns out the problem was that same
as the author's situation, only the damaged component in my case was a result of
wear and tear - not sabotage.
What's Your EQ?
Three puzzlers for the student, theoretician end practical man. Simple? Double-check
your answers before you soy you've solved them. If you have an interesting or unusual
puzzle (with an answer!) send it to us. We will pay $10 for each one accepted. We're
especially interested in service stinkers or engineering stumpers on actual electronic
equipment. We get so many letters we can't answer individual ones, but we'll print
the more interesting solutions - ones the original authors never thought of. (Solutions
at bottom of page)
Write EQ Editor, Radio-Electronics, 154 West 14th Street, New York 11, N. Y.
10011.
Two Resistors
What is the value of R1 and R2?
- Steve Stumph
Why No Voltage?
In checking a power supply as in the schematic, the dc output voltage was just
about right, but there was no ac voltage from X to Y. The transformer was not overheating.
With the power supply disconnected and the filter capacitors discharged, a resistance
check was made from X to Y, proving that both halves of the secondary were intact.
Why could no voltage be read between X and Y with the circuit operating? - Sid Elliot
Where's the TVI?
Very severe TVI: Heavy "bands of dots" or partial blackouts on TV screens all
over town, whether on antennas or on the "cable", the community antenna system.
(Their antennas were 3 miles from town and 1,000 feet higher.) Both channels affected
were low-band stations, almost adjacent, to the east. Stations to the south were
not affected.
Using simple methods, the source of the interference was located, reported and
fixed. (Hint: This is a "fringe-area" town.) - Jack Darr
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
|
-
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
|
Answers to Puzzles on p. 54
Two Resistors
The two resistors in series add up to 100 ohms: R1 + R2 = 100.
In parallel, they make 10 ohms:
R1R2/(R1 + R2) = 10.
Since we know that R1 + R2 = 100, we can substitute in the "parallel" equation
and get R1R2/100 = 10, or R1R2 = 1,000. Now we have two equations in two variables,
and we can solve them.
Expressing R2 in terms of R1 , we can write R2 = 100 - R1 (from our "series"
equation above). This gives us R1 (100 - R1) = 1,000, or
100R1 - R12 = 1,000.
This is a simple quadratic equation. Let's rearrange it into standard form: R12
- 100R1 + 1,000 = 0. Now we can use the quadratic formula (see any algebra textbook).
If we substitute either R1 value into the "series" equation R1 + R2 = 100, or
R2 = 100 - R1 (same thing), we'll get a value for R2, and the problem is solved.
Notice how the two roots of the equation, 88.73 and 11.27, add up to 100. In other
words, we can pick either value as R1, and the other is automatically R2. Try it.
Here is the Complete the Square Method (by Kirt Blattenberger):
Start with the author's easily obtained equation for R1 (could be R2 with same
result) -
100R1 - R12 = 1000 => R12
- 100R1 + 1000 = 0
Rewrite as {(R1 - 50)2} +1000 = (-50)2
{R12
- 100R1 + 2500} + 1000 = 2500
(R1
- 50)2 = 2500 - 1000
(R1
- 50)2 = 1500
(R1
- 50) = ± √(1500)
R1
= ± √(1500) + 50
R1
= 50 ± √(1500) = 50 ± √(15 * 100) = 50 ± 10*√(15) = 50 * ±38.73
R1
= 11.27 Ω, 88.73 Ω
R2
= 100 - {11.27 Ω, 88.73} = 88.73 Ω, 11.27 Ω
Why No Voltage?
The power transformer had a "balanced" secondary - a rare unit in which the two
secondary halves were wound side by side, so that each had equal resistance as well
as equal inductance. But the leads on one of the halves had been reversed. Thus
X and Y were effectively in parallel, and the circuit was working as a half-wave
rectifier.
Where's the TVI?
Since the interference was being picked up on the cable antennas far above the
town, it was obviously a very high-intensity source. Since it did not interfere
with stations to the south, it had to be toward the east.
Going to three homes in town which had high-gain directional antennas and rotors,
we shot bearings on the noise, turning the antennas for maxi-mum interference. These
bearings were marked on a city map.
An aerial-navigation chart of the area showed a 67,000-volt power line running
along the highway going north. Checked out with an auto radio, the cause of the
interference was very apparent. Someone had shot an insulator, and the high voltage
was arcing through the streak of lead. Because of the direction of the lines, as
seen in the figure, they acted as a very efficient transmitting antenna to radiate
the interference toward the town and community antenna.
Posted October 10, 2023
|