Capacitor Circuit Quiz
June 1968 Popular Electronics

June 1968 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.

Here is a good quiz on calculating total equivalent capacitance for circuits containing various combination of series, parallel, and series-parallel connections. It appeared in the June 1968 issue of Popular Electronics magazine. To help in calculation, all of the individual capacitor values are the same. Many of them you can probably solve in your head, especially if you mentally rearrange the circuit into a more readily recognizable configuration. For instance, circuit #1 can be redrawn having two parallel branches across the source. One branch has just a single capacitor while the other has two parallel capacitors in series with one capacitor. The equation is then C + (2C²/3C) = C + 2/3C = 5/3C. For C = 6 pF, C_total = 5/3*6 pF = 10 pF.

Capacitor Circuit Quiz

by Robert P. Balin

Capacitors are not only used as single units in electronic circuits, but are often combined in series or parallel with other capacitors. When connected in series, capacitors add like resistors in parallel. The exact formula for adding any two out of any number of capacitors in series is: C_T = C1 x C2/C1 + C2. When connected in parallel, capacitors add like resistors in series, so that the total capacitance is equal to the sum of the separate values. To test your skill at working capacitor problems, try to find the total effective capacitance available in each of the circuits (1-10) shown below. Each capacitor is rated at 6 pF. Hint: Beware of capacitors that might be shorted out. Answers are at the bottom of the page.

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.

1)  10 pF

2)  6 pF

3)  12 pF

4)  9 pF

5)  16 pF

6)  8 pF

7)  5 pF

8)  3 pF

9)  15 pF

10) 4 pF

Posted April 26, 2023
(updated from original post on 7/4/2013)