Diode Switch Circuit Quiz
July 1961 Popular Electronics

July 1961 Popular Electronics Table 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.

Test your diode switch analysis skills here with six circuits designed by Mr. Robert P. Balin in the July 1961 issue of Popular Electronics. When evaluating the equivalent circuits with the diodes biased on or off, don't make the job more difficult for yourself by considering whether there is enough voltage or current to turn a particular diode on or not, just whether the diode is forward or reverse biased. Doing so reduces everything to simple series and parallel combinations. Redrawing each circuit either with a short for a forward biased diode and an open for a reverse biased diode makes the task easier.

If you like diode quizzes, here is another from the August 1965 issue of Popular Electronics.

Diode Quiz

By Robert P. Balin

Keeping in mind that a diode can pass current in one direction only, see if you can find the effective resistance across the battery in the circuits below. Assume that every resistor measures six ohms, and that the diodes have zero resistance in the forward direction, infinite resistance in the reverse direction.

See answers below.

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.

Diode Quiz Answers

1.   2 ohms

2.   6 ohms

3.   3 ohms

4.   9 ohms

5.   6 ohms

6.   2 ohms

Posted July 25, 2019
(updated from original post on 4/13/2014)