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What's Your EQ?
September 1964 Radio-Electronics

September 1964 Radio-Electronics

September 1964 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.

Are you in a mood to take this "What's Your EQ?" (Electronics Quotient) challenge from E. D. Clark? Appearing in the September 1964 issue of Radio-Electronics magazine, it is one of dozens he conjured up with the assistance of readers. "What's in the Box" is pretty straight-forward if you take the designer's advice and not try to over-think the problem. I was easily able to come up with a circuit for explaining the changes in capacitance and resistance, but didn't think of the additional mechanism to cause the change to occur as specified. You'll probably do better. There are people in the RF Cafe audience that can resolve the "Reverse Polarity" problem, but they are very few and very far between (and I'm not one of them). That one requires that you've "Been there. Done that."

What's Your EQ?

What's Your EQ (Electronics Quotient)?,September 1964 Radio-Electronics - RF CafeTwo puzzlers for the students, theoretician and practical 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.

Answers to this month's puzzles are on page 105.

Conducted by E. D. Clark

What's in the Box? - RF CafeWhat's in the Box?

I have presented this problem to many technicians and, though the answer is simple, they have failed to find it. This, I think, is due to the fact that they tend to complicate a simple problem.

Before the switch is closed, the capacitance bridge reads 5 pf, and the ohmmeter reads 1 ohm. After the switch is closed, the bridge reads 50 pf, and the ohmmeter 5 ohms. Reverse battery polarity, and readings revert to original. Voltage check at terminals A-B shows no voltage present. What's in the black box?

- E.J. Cunningham

 

Reverse Polarity - RF CafeReverse Polarity

In trouble-shooting a 40-mc, 100-watt mobile transmitter, all electrode voltages as measured with a standard 20,000 ohms per volt vom agree with the manufacturer's schematic - except that the voltage at the plates of the 7055 (12AL5) audio limiter is a negative 13 volts! A new-tested tube results in the same reading. What is wrong? Hint: An 11-meg vtvm reads a positive 13 volts, but when both meters are connected to the plates, both read -13 volts.

 - Basil Barbee

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?

This month's puzzles are on page 59

What's in the Box? Solution - RF CafeWhat's in the Box?

After taking the "lid" off of the box, we see two resistors, two capacitors, a dpdt relay and a diode. They are connected as shown in the diagram with relay contacts in the de-energized position.

Reverse Polarity

The vom leads picked up rf from the antenna, which when shunt-rectified by the diodes, resulted in a negative-dc voltage sufficient to overcome the positive 13 volts from the power supply, with 13 volts left over!

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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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