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What's Your EQ?
July 1967 Radio-Electronics

July 1967 Radio-Electronics

July 1967 Radio-Electronics Cover - RF Cafe[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.

Only two circuit challenges were presented in the July 1969 "What's Your EQ?" feature in Radio-Electronics magazine. "EQ," or Electronics Quotient, is a play on "IQ," Intelligence Quotient. EQs are submitted by readers, although occasionally one of the magazine editors contributes. "Lamp Switching" is a classical puzzle where a mechanical switch and a handful of steering diodes are connected, and your mission, if you choose to accept it, is to figure out what is inherently wrong with the way the author constructed his circuit. He admits it didn't work as planned, and invites you to come to the same conclusion as to why it didn't work. He does not tell what the "strange things" that happened were. The Black Box challenge asks for the simplest voltage doubler circuit, stating only that it cannot contain a battery, coil, or moving part. My answer would be, given the high input impedance (megohms, typically) VTVM measuring the output, a capacitor charged to 6 volts in series with the input. He did not specify how long the output would need to maintain the 12 volts ;-)

What's Your EQ?

Conducted by E. D. Clark

Two puzzlers for the student, theoretician and practiced man. Simple? Double-check your answers before you say 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.

Write EQ Editor, Radio-Electronics, 154 West 14th Street, New York, N. Y. 10011.

Lamp Switching - RF CafeAnswers to this month's puzzles are on page 89.

Lamp Switching

I wanted a circuit using lamps, diodes and a single-pole 5-position switch to turn on various combinations of 5 lamps as follows (1) lamps 1 and 3, (2) lamps 2 and 3, (3) lamps 3 and 5, (4) lamps 3 and 4; (5) lamps 5 and 1.

I built the circuit shown, but when I turned it on, strange things happened. What happened and what must be done to correct the circuit?

- Herschel P. Hall

 

Black-Box Voltage Doubler - RF CafeBlack-Box Voltage Doubler

What can be the simplest circuit inside the box to double the voltage as shown? The box does not contain a battery, coil or moving part.

- C. S. S. Shenoi

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 Quizzes

Vintage Electronics Magazine Quizzes

Vintage Electronics Magazine Quizzes

Vintage Electronics Magazine Quizzes

Answers to What's Your Eq?

These are the answers. Puzzles are on page 78.

Lamp Switching Solution - RF Cafe

Lamp Switching

As shown, the circuit will fire the desired lamps - but also some others. They come on as follows: (1) 1, 3, 5;

(2) 1, 2, 3, 5; (3) 1, 3, 5; (4) 1, 3, 4, 5; (5) 1 3 5.

The circuit operates correctly when connected as shown above.

 

Black-Box Voltage Doubler Solution - RF CafeBlack-Box Voltage Doubler

The box contains an RC phase-shift oscillator and a voltage-doubler rectifier, as shown.  
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About RF Cafe

Kirt Blattenberger - RF Cafe Webmaster

Copyright: 1996 - 2025
Webmaster: Kirt Blattenberger,
   BSEE - KB3UON - AMA92498

RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while tying up your telephone line, and a lady's voice announced "You've Got Mail" when a new message arrived...

Copyright  1996 - 2026

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