May 1966 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.

The circuit drawings in this Series
Circuit Quiz are a little hard to read in a few places because the original page used
light red on top of a gray background. The magic of image processing did a pretty good
job of cleaning them up to where you shouldn't have any trouble reading them. This quiz
from Robert Balin appeared in the April 1966 issue of Popular Electronics. It
is one of the easier, so don't tell anyone if you score less than 100% ;)
Series Circuit Quiz
By Robert P. Balin
Experimenters often have to connect similar electronic components  resistors, capacitors,
coils, etc.  in series to obtain a desired value or effect. This deceptively simple
task requires an understanding of the basic operating principles of the components. See
how many of these True /·False questions you can answer correctly by first working out
each problem.
1. If two capacitors are connected in series
across a voltage source, the smaller one will charge up to the larger proportion of the
applied voltage.
True _
False _

6. If two voltmeters, each set on the same
scale, are in series across a voltage source, the one with the higher ohms/volt rating
gives the greater deflection.
True _
False _

2. If two lamps of equal voltage and wattage
rating are connected in series across a power source, each will deliver onehalf of its
rated power.
True _
False _

7. If the filaments of a 6V6 and a 12SQ7
electron tube are wired in series, the tubes will operate satisfactorily when connected
across an 18volt source.
True _
False _

3. If two s.p.s.t. switches are connected
in series with a battery and a lamp. the arrangement may be considered the same as an
"OR" logic circuit.
True _
False _

8. Two 100ohm resistors placed across a
battery having an internal resistance of 100 ohms dissipate twice as much power as one
of the external resistors.
True .
False _

4. If a 3ohm, 2watt speaker and a 6ohm,
1watt speaker are connected in series, the 1watt speaker will deliver twice as much
power as the 2watt speaker .
True _
False _

9. If the two secondary windings of a transformer
are in series as shown, the output voltage is the sum of the individual secondary coil
voltages.
True _
False _

5. If two dry cells of equal current and
voltage rating are connected in series across a load, the currenthandling capability
of the circuit is increased twofold.
True _
False _

10. If a 500ohm. 5watt resistor and a
500ohm, 10watt resistor are in series across a 100volt source, they are considered
equal to a 1000ohm, 15watter.
True _
False _

See answers below.
Popular Electronics published many quizzes over the years
 some really simple and others not so simple. Robert Balin created many of the quizzes.
This is a listing of all I have posted thus far.
 Electronic
Switching Quiz  October 1967
 Electronic
Angle Quiz  September 1967
 International
Electronics Quiz  July 1967
 Bridge Circuit
Quiz December 1966
 Diode Function
Quiz  August 1965
 Diagram Quiz, August
1966
 TV Trouble Quiz,
July 1966
 Electronics History Quiz,
December 1965
 ScopeTrace Quiz,
March 1965
 Electronic
Circuit Analogy Quiz, April 1973
 Test
Your Knowledge of Semiconductors, August 1972
 Ganged Switching
Quiz, April 1972
 Lamp Brightness
Quiz, January 1969
 Lissajous Pattern Quiz, September 1963
 Electronic
Quizoo, October 1962
 Electronic Photo Album Quiz, March 1963
 Electronic Alphabet Quiz, May 1963
 Quiz: Resistive?
Inductive? or Capacitive?, October 1960
 VectorCircuit Matching Quiz, June 1970
 Inductance
Quiz, September 1961
 RC Circuit
Quiz, June 1963
 Diode Quiz,
July 1961
 Electronic Curves Quiz, February 1963
 Electronic Numbers Quiz, December 1962
 Energy Conversion Quiz, April 1963
 Coil
Function Quiz, June 1962

 Unknown Frequency
Quiz  September 1965
 Electronics
Metals Quiz  October 1964
 Electronics
Measurement Quiz  August 1967
 MeterReading Quiz,
June 1966
 Electronic
Geometry Quiz, January 1965
 Electronic
Factor Quiz, November 1966
 Electronics
Math Quiz, November 1965
 Series Circuit Quiz,
May 1966

Electrochemistry Quiz, March 1966
 Electronic Analogy
Quiz, November 1961
 Electronic
Coupling Quiz, August 1973
 Electronics Analogy Quiz, August 1960
 Audio Quiz,
April 1955
 Electronic
Unit Quiz, May 1962

Capacitor Circuit Quiz, June 1968
 Quiz on AC Circuit Theory, December 1970
 Magnetic Phenomena Quiz, February 1962
 Electronics Geography Quiz, April 1970

Electronic Menu Quiz, August 1963
 Electronic Noise Quiz, August 1962
 Electronic Current Quiz, October 1963
 Electronic Inventors Quiz, November 1963
 Resistor
Function Quiz, January 1962
 Electronic Measurement Quiz, January 1963
 Vacuum
Tube Quiz, February 1961
 KoolKeeping Kwiz, June
1970

Quiz Answers
1. True. With unequal capacitors in series, the voltage across each capacitor is inversely
proportional to its capacitance. This is shown by the formula E = Q/C, where Q, the number
of electrons moving in the circuit, is the same for both capacitors.
2. False. Since the lamps have the same resistance, the applied voltage and the current
in the circuit will be reduced by a factor of onehalf. And, since P = EI, each lamp
will operate at onefourth its rated power.
3. False. As shown, S1 and S2 must both be closed before the lamp will light, so that
the arrangement forms an "AND" circuit.
4. True. Each speaker will receive the same amount of current from the source, and,
since P = I^{2}Z, the power developed will be a function of the voice coil impedance,
Z. The 6ohm speaker produces twice the power of the 3ohm speaker for the same input.
5. False. Although the total voltage across the two cells in series equals the sum
of the individual cell voltage, like two similar fuses in series, the currenthandling
capability of the circuit is not altered.
6. True. Voltmeter sensitivity is a product of its ohms/volt rating and the scale
setting. On the 5volt scale, the resistance of the 20,000 ohms/volt meter is 100,000
ohms, while the resistance of the 10,000 ohms/ volt meter is 50,000 ohms. The voltage
drop across the 20,000 ohms/volt meter is greater than the drop across the other meter,
giving a greater deflection.
7. False. From the tube manual, a 6V6 draws 450 ma, while a 12SQ7 draws only 150 ma.
From Ohm's law, the filament resistances are, respectively, 13 ohms and 80 ohms. Therefore,
the current in the series circuit would be approximately 200 ma., placing 2.6 volts across
the 6V6, and more than 15 volts across the 12SQ7.
8. False. Since P = I^{2}R, the reduced current resulting from two resistors
instead of one has a greater effect on the power dissipation than does an increase in
resistance.
9. True. The polarity marks indicate that the secondary voltages are in phase and
are seriesaiding. Thus, the output voltage is the sum of the two secondary voltages.
10. False. Since a current of 100 ma. flows in the circuit, the power dissipated by
each resistor is 5 watts (P = EI) for a total dissipation of 10 watts. If a 1000ohm
resistor is substituted for the two 500ohm units, the power dissipation remains at 10
watts (by the same formula).
Posted April 9, 2018
