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. All copyrights (if any) are hereby acknowledged.
Robert Balin created many quizzes for Popular Electronics
magazine back in the
1960s and 1970s. This particular Electronic Numbers Quiz presents various objects and your
challenge is to match one of the provided numerical values to each item. For example, a
tuning fork is most commonly, in the Western world, associated with a certain frequency for
tuning musical instruments (electronic and mechanical). As is often the case, being familiar
with the "standards" of the era is helpful on a few of the items like the tuning capacitor
and the IF transformer, but you should be able to eliminate some options by knowing the
impedance of the twin lead transmission line and the phase relationship of current and
voltage in a pure inductance.
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Electronic Numbers Quiz
By Robert P. Balin
Anyone in electronics gets to know many numbers, each of which
relates primarily to some specific circuit or component. Why not try your luck at matching the
eight numbers below with the drawings (A - J) to which they most logically refer?
1.414 - F The maximum or peak value of a Sine
Wave is 1.414 times its effective or r.m.s value.
- C A common impedance for Speaker voice coils is 3.2 ohms.
47 - A A type 47 Pilot Lamp is the one almost always found in the "All-American
90 - H Current through
a pure Inductance lags the applied voltage by a quarter of a cycle, or 90 degrees.
140 - G A common maximum capacitance value for a Variable Capacitor is 140 μμf.
180 - B A signal fed into a Vacuum Tube between
grid and ground is inverted, or shifted 180° in phase,
when observed between plate and ground.
300 - J
The impedance of TV and FM Twin Lead is 300 ohms.
440 - E
A Tuning Fork used to tune musical instruments vibrates at 440 cycles, or A above middle C.
455 - I A common frequency for an I.F. Transformer
is 455 kc.,
15,750 - D The frequency of the horizontal sweep oscillator
in a TV Set is 15,750 cycles. Posted March