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 another electronics quiz for you to try. Intuition from experience
goes a long way here, but if all else fails you can work out the
details of the rectifier circuits to determine which lamp received
the most current. Keep in mind that the diode symbols are not
LEDs; it is the 'A,' 'B,' and 'C' symbols inside circles that are
the lamps whose brightnesses are being considered. LEDs did exist
at the time this quiz was created in 1969, but the circuits would
perform differently if in fact LEDs were used for double duty of
rectification and illumination. Good luck. Answers are at the bottom.
Lamp Brightness Quiz
By Robert P. Balin
The brightness of a lamp operated on a.c. depends on the average
current through its filaments during each cycle. A rectifier connected
in series or parallel with the lamp can be used to control the current
on alternate half cycles. In lamp circuits, current paths and individual
lamp brightness may be considerably altered, and some interesting
effects produced. To test your ability to analyze lamp and rectifier
circuits, try to determine which lamp is the brightest in each of
the ten circuits shown here. Assume that the diodes have zero forward
resistance and infinite back resistance and that all lamps and supplies
are identical.
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.
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 typing up your telephone line, and a nice lady's voice announced "You've Got
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