  # Electronics Math QuizNovember 1965 Popular Electronics

 November 1965 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.

1965 was near the beginning of the transition from vacuum tubes (plasma state) to semiconductors (solid state). If you are not familiar with tube circuits, when deciding what type of mathematical operation is being performed by each circuit, mentally replace the tube with a FET or a BJT. The tube plate becomes the transistor drain or collector, the cathode is the source or emitter, and the control grid is the gate or base, respectively. Don't worry about biasing. Circuits A, D, and I should prove to be the easiest. Circuit F is pretty obvious if you look at the input and output waveforms shown. Anyone familiar with analog power supplies will breeze through circuits B and G (hint: count the number of charge storage components). For the others, ignore that there is a squarewave shown at the input since the function is not dependent on a squarewave to work. For circuit H, mentally reposition the bottom tube above the other and have the B+ line point upward, then figure out what happens as each turns on. It was common to draw B+ lines pointing downward whereas in transistor circuits they normally point upward or sideward. Think of the two tubes in circuit E as parallel resistors changing value (point B+ upward). Circuit C takes a bit of work (hint: the circuit is a detector). Circuit J is the toughest of all, but if you get the other 9 correct, only one possible answer remains from which to choose - that's how I scored 10:10.

## Electronics Math Quiz

By Robert P. Balin

Many basic electronic circuits can and do perform mathematical operations ranging from elementary arithmetic to integral calculus. See if you can identify the electronic circuits (A-J) below which perform the mathematical operations (1-10) at right. 2) Count ____________

3) Differentiate ____________

4) Double ____________

5) Divide ____________

6) Integrate ____________

7) Ratio ____________

8) Square ____________

9) Subtract ____________

10) Triple ____________

Popular Electronics published many quizzes over the years - some really simple and others not so simple. Robert P. Balin created many of the quizzes. This is a listing of all I have posted thus far.

 A Baffling Quiz - January 1968 Electronics IQ Quiz - May 1967 Plug and Jack Quiz - December 1967 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 Scope-Trace 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 Vector-Circuit 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 Amplifier Quiz Part I - February 1964 Semiconductor Quiz - February 1967 Unknown Frequency Quiz - September 1965 Electronics Metals Quiz - October 1964 Electronics Measurement Quiz - August 1967 Meter-Reading 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 Kool-Keeping Kwiz, June 1970 Find the Brightest Bulb Quiz, April 1960

1 - H   Amplifiers which have their load resistors in series produce an output signal proportional to the sum of the in-phase input signals.

2 - F   A step counter produces an escalated output which varies exponentially with the number of pulses it receives. It can be used to count the number of pulses it receives, and as a frequency divider by allowing it to trigger another circuit, say at every 2nd, 3rd ... 7th step, as desired.

3 - I   A differentiator circuit produces an output whose instantaneous values are proportional to the rate of change of the input voltage waveform.

4 - G   A voltage doubler produces a d.c. output which is approximately equal to twice the r.m.s. value of the a.c. input voltage.

5 - D   A voltage divider provides an output which is in the same proportion to the applied voltage as the divider resistance is to the total resistance.

6 - A   An integrating circuit provides an output voltage which is approximately proportional to the time integral and potential of the input voltage.

7 - J   In a ratio detector circuit, the variations of audio frequency output signals have the same ratio as the variations of the applied FM radio frequency signals.

8 - C   A triode square law detector produces an output signal which is proportional to the square of the input signal.

9 - E   A differential amplifier produces an output signal whose amplitude is proportional to the difference between two in-phase input signals.

10 - B   A voltage tripler circuit produces a d.c. output which is approximately equal to three times the r.m.s. value of the a.c. input voltage.

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