Search RFCafe.com                           
      More Than 17,000 Unique Pages
Please support me by ADVERTISING!
Serving a Pleasant Blend of Yesterday, Today, and Tomorrow™ Please Support My Advertisers!
   Formulas & Data
Electronics | RF
Mathematics
Mechanics | Physics
     AI-Generated
     Technical Data
Pioneers | Society
Companies | Parts
Principles | Assns


 About | Sitemap
Homepage Archive
        Resources
Articles, Forums Calculators, Radar
Magazines, Museum
Radio Service Data
Software, Videos
     Entertainment
Crosswords, Humor Cogitations, Podcast
Quotes, Quizzes
   Parts & Services
1000s of Listings
 Vintage Magazines
Electronics World
Popular Electronics
Radio & TV News
QST | Pop Science
Popular Mechanics
Radio-Craft
Radio-Electronics
Short Wave Craft
Electronics | OFA
Saturday Eve Post

Software: RF Cascade Workbook
RF Stencils Visio | RF Symbols Visio
RF Symbols Office | Cafe Press
Espresso Engineering Workbook

Aegis Power  |  Alliance Test
Centric RF  |  Empower RF
ISOTEC  |  Reactel  |  RFCT
San Fran Circuits

Copper Mountain Technologies (VNA) - RF Cafe

Innovative Power Products Cool Chip Thermal Dissipation - RF Cafe

ConductRF Phased Matched RF Cables - RF Cafe

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

Quiz on AC Circuit Theory
December 1970 Popular Electronics

December 1970 Popular Electronics

December 1970 Popular Electronics Cover - RF CafeTable 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.

Here is a fairly simple quiz on AC circuit analysis that appeared in the December 1970 issue of Popular Electronics magazine. If you are not already comfortable with adding series and parallel circuits containing resistors, capacitors, and inductors, you will appreciate the simple formula presented that will keep the sweat level down ;-) . An even simpler form that solves explicitly for the four variables are as follows:

VTotal = √ [(VL - VC)2 + VR2]

VR = √ [(VT)2 - (VL - VC)2]

VL = VC + √ [VT2 - VR2]

VC = VL - √ [VT2 - VR2]

      OK, pick up your pencils and begin ... now.

Quiz on AC Circuit Theory

AC Circuit Theory Quiz, December 1970 Popular Electronics - RF CafeBy Robert P. Balin

Voltage measurements made in a series ac circuit seldom add up as simply as they do in a dc circuit. You may even find the voltage across a coil or capacitor to be greater than the supply voltage! Nevertheless, Ohm's Law and Kirchhoff's Law do apply, and careful measurements will show that the supply voltage and the various voltage drops around a series ac circuit are related in an unusual way: the square of the supply voltage is equal to the square of the difference between the voltage on the coil and the voltage on the capacitor, plus the square of the voltage on the resistor.

This relationship, VTotal2 = (VL - VC)2 + VR2,can be used to find any unknown voltage if all others are known.

In parallel ac circuits, the currents add up the same way as voltages do in a series ac circuit. Brush up on your ac theory and see if you can solve the missing voltage or current in the circuits below. Where necessary, the voltages and currents are related by the 3:4:5 ratio to provide easy, whole number answers. Only simple algebra is required. Vectors, phasors, and quadratic equations are not necessary to find the solutions.

 

(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 Quizzes

Vintage Electronics Magazine Quizzes

Vintage Electronics Magazine Quizzes

Vintage Electronics Magazine Quizzes

 

 

 

 

 

 

 

 

 

 

 

 

Circuit Quiz Answers

1. (10)2= (8)2 + (VR)2; VR = 6V

2. (20)2= (7+VC)2+ (12)2; VC = 9V

3. (24)2= (VL-6)2; VL = 30V

4. (15)2= (350-350)2+ (VR)2; VR = 15V

5. (VT)2= (15-3)2+ (16)2; VT = 20V

6. (50)2= (VL)2+ (12)2= (VC)2+ (12)2; VL = VC

    (VT)2= (VL-VC)2+ (12)2; VT = 12V

7. (IT)2= (6)2+ (8)2; IT = 10 mA.

8. (20)2= (16-IC)2+ (16)2; IC = 4 mA.

9. (IT)2= (17-13)2+ (3)2; IT = 5 mA.

10. (9)2= (40-4-IC)2; IC = 7 mA.

 

 

Posted May 1, 2023
(updated from original post on 6/21/2013)

Windfreak Technologies SynthHD PRO - RF Cafe


Crane Aerospace Electronics Microwave Solutions

Anatech Electronics RF Microwave Filters - RF Cafe