Electronics World articles Popular Electronics articles QST articles Radio & TV News articles Radio-Craft articles Radio-Electronics articles Short Wave Craft articles Wireless World articles Google Search of RF Cafe website Sitemap Electronics Equations Mathematics Equations Equations physics Manufacturers & distributors LinkedIn Crosswords Engineering Humor Kirt's Cogitations RF Engineering Quizzes Notable Quotes Calculators Education Engineering Magazine Articles Engineering software RF Cafe Archives Magazine Sponsor RF Cafe Sponsor Links Saturday Evening Post NEETS EW Radar Handbook Microwave Museum About RF Cafe Aegis Power Systems Alliance Test Equipment Centric RF Empower RF ISOTEC Reactel RF Connector Technology San Francisco Circuits Anritsu Amplifier Solutions Anatech Electronics Axiom Test Equipment Conduct RF Copper Mountain Technologies Exodus Advanced Communications Innovative Power Products KR Filters LadyBug Technologies Rigol TotalTemp Technologies Werbel Microwave Windfreak Technologies Wireless Telecom Group Withwave RF Cafe Software Resources Vintage Magazines RF Cafe Software WhoIs entry for RF Cafe.com Thank you for visiting RF Cafe!
Copper Mountain Technologies (VNA) - RF Cafe

Cafe Press

everythingRF RF & Microwave Parts Database (h1)

Please Support RF Cafe by purchasing my  ridiculously low-priced products, all of which I created.

RF Cascade Workbook for Excel

RF & Electronics Symbols for Visio

RF & Electronics Symbols for Office

RF & Electronics Stencils for Visio

RF Workbench

T-Shirts, Mugs, Cups, Ball Caps, Mouse Pads

These Are Available for Free

Espresso Engineering Workbook™

Smith Chart™ for Excel

Windfreak Technologies SynthHD PRO - RF Cafe

What's Your EQ?
January 1967 Radio-Electronics

January 1967 Radio-Electronics

January 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.

The January 1967 instance of Radio-Electronics magazine's "What's Your EQ?" challenge contains only two puzzles. The first is a variation on the classic resistor mesh wherein a matrix of series and parallel resistors, all of a common value (10 Ω), are wired together, and your job is to determine what total resistance would be measured between the indicated two points. Author E.D. Clark implicitly suggests taking a good look at the schematic to simplify it before diving into it with circuit analysis equations. Maybe cross your eyes a bit and cross-focus like you do with those 3D images that were popular a couple decades ago. You'll be amazed (see what I just did there?) at how simple it is to calculate the equivalent resistance. The second puzzle takes a bit more work. No restrictions are placed on what additional components can be inside the boxes. To clarify, if the top switch and bulb are labeled "A" and the bottom one "B," then switch "A" switch independently controls (on or off) only bulb "A" and switch "B" switch independently controls (on or off) only bulb "B." The third wire mentioned for a simple connection would be a common point for the current flow.

What's Your EQ?

What's Your EQ?, August 1964 Radio-Electronics - RF CafeConducted by E. D. Clark

Two puzzlers for the student, 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 99.

 

Resistor Network - RF CafeResistor Network

Another insomniac's RT nightmare.

Forget about Kirchhoff's laws and loop-circuit calculations, though. Study the diagram carefully for about 30 seconds.

What's the total resistance at the terminals?

    - Dennis Howard

 

Light Switching Circuit - RF CafeLight Switching Circuit

Either one or both of the lamps in box B may be turned on by throwing either one or both of the switches in box A. In normal electrical work, this hookup would require three conductors between the boxes, not two, as shown.

What's inside the boxes and how is everything wired?

    - Jim Wilhelm


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.

RF Cafe Quizzes

Vintage Electronics Magazine Quizzes

Vintage Electronics Magazine Quizzes

These are the answers. Puzzles are on page 61.

Resistor Network

The total resistance is 2/5 ohm. Yes, all resistors are in parallel!

 

Light Switching Circuit Solution - RF CafeLight Switching Circuit

The reverse resistance of the diodes (any receiving-type silicons) blocks current flow to both lamps when both switches are open. When S1 is closed, current flows through D3, L1, D2, lighting L1. But current cannot flow through L2 because D2 and D4 are back to back in series with L2, blocking current flow on both half-cycles of the ac.

 

 

Posted November 29, 2023

Windfreak Technologies SynthHD PRO - RF Cafe
Innovative Power Products Passive RF Products - RF Cafe

ConductRF Phased Matched RF Cables - RF Cafe

TotalTemp Technologies (Thermal Platforms) - RF Cafe