class, put your books away and take out a pencil. Spread your chairs out because we're going to
have a quiz today. A collective sigh permeates the room. Remember those days? I still have nightmares
over those moments, and they were decades ago for me. At least this "Electronic Noise Quiz" from
the August 1962 edition of Popular Electronics won't affect your GPA. Sometimes PE's
quiz illustrations are kind of hard to interpret, but this one does a pretty good job (except
item 'E', but I'm not telling what it is since nobody helped me). You will need a fairly diverse
background in consumer type electronics to do well, and having a few gray hairs will probably
help as well. Good luck. BTW, my score was 80%.
[Table of Contents]People old and young enjoy waxing
nostalgic about and learning some of the history of early electronics. Popular Electronics was published from October
1954 through April 1985. As time permits, I will be glad to scan articles for you. All copyrights (if any) are hereby
See all articles from
By Robert P. Balin
The noises that electrical and electronic
devices make can indicate normal operation or trouble, and a clever technician trains his ear
to distinguish one from the other. Test your noise knowledge by matching the 10 noises listed
below with the drawings (A-J) of the devices that usually produce them.
Electronic Noise Quiz Answers
1 - B) Transformer buzz is usually produced by the vibration
of loose laminations in the transformer's iron core.
2 - H) Relay chatter occurs when the current value in the relay coil
is somewhere between the normal operating value and the drop-out value.
3 - I) Turntable rumble is a low-frequency vibration mechanically
transmitted to the phono cartridge pickup by the turntable drive mechanism.
4 - G) Keying chirp is caused by undesirable variations in transmitted
frequency when the transmitter r.f. oscillator is keyed.
5 - J) Armature growl is a symptomatic sound made by an armature
containing shorted turns when placed on a test-stand device called a "growler."
6 - A) Loudspeaker boom is produced by self-oscillation of the speaker
at a low-frequency resonant point.
7 - E) Needle scratch is due to a worn stylus point. Dirt and dust
on a record or a defective record can produce the same sound.
8 - C) Tube hiss is due to electron collisions in an irregular electron
stream caused by an uneven cathode coating. Although a tape recorder (F) and a car generator (D)
will also produce hiss, they are not the correct answers for question 8, but for 9 and 10 which
9 - F) Tape recorder wow is comprised of slow variations in the pitch
of recorded sounds caused by irregular slippage or drag in the tape drive mechanism. A turntable
(I) with a friction drive will also produce wow sounds, but (I) has already been matched with
10 - D) Generator whine is due to commutator sparking and changes
in frequency with varying engine speeds, and it sometimes interferes with reception in or from