Quizzes - Recent Threads

World Engineering Day Quiz!

ambugua — Wed, 04 Mar 2026 14:16:00 GMT

A checkerboard made as a 7 x 7 matrix has a green basic cell placed in its middle as shown in the above structure.

Questions:

How many squares, defined in that matrix, are covering the green cell?
Can you extend the problem to any matrix size (i.e., n * n with n odd)? For example, what would be the answer for a 99 * 99 matrix?

KCC's Quizzes AQQ297 about taking the right dose of medication

KCC — Fri, 13 Feb 2026 10:51:20 GMT

1. First, the quote of the month: "All my life I though air is free until I bought a bag of chips" - unknown

2. New quiz AQQ297 about taking the right dose of medication:

A person has a rare medical condition. Every day, he must take a dose of 1 tablet of
medicine A and 1 tablet of medicine B. If he misses the right dose, he can be in
danger. Unfortunately, the tablets look identical.
He was enjoying a vacation when bad luck strikes. With 2 days left, he clumsily drops
the 4 remaining tablets on the floor and they get mixed up.
There is no way to get more medicine.
Questions:
1. How should he proceed to still be able to take his medicine correctly?
2. If the situation is 3 days left

Good luck and try to be among the first ones!

P.S. Inform your friends and colleagues about those quizzes if you think they can be interested. The deep link is:

https://ez.analog.com/

KCC's Quizzes AQQ296 about repairing an equation in a digital display

KCC — Fri, 09 Jan 2026 15:20:12 GMT

1. Quote of this month: "When I die, I want to die like my grandfather who died peacefully in his sleep. Not screaming like all the passengers in his car." - Will Rogers

2. New challenge AQQ296 about repairing an equation in a digital display:

A digital system expresses the equation (10+1) * (10-1) = 101 on a dots
matrix display. The equation is obviously incorrect.
By witching off, 2 dots in that display, it is possible to validate the equation.

Question:
Which dots are you changing and what's the equation you obtain?

Good luck and try to be among the first ones!

KCC's Quizzes AQQ295 about an audio logarithmic volume controller using linear pot - a proposal from Tim O'Brien

KCC — Fri, 12 Dec 2025 12:50:56 GMT

1. Quote of the month: "Think like a proton. Always positive" - Unknown

2. New quiz of the month: AQQ295 about a audio logarithmic volume controller using linear pot circuit

A kind proposal from Tim O’Brien (a frequent participant to our quizzes)

Audio volume is usually controlled by a logarithmic (log) potentiometer (pot) to approximate human hearing response. However true log pots are increasingly hard to source and relatively expensive. But there is a simple trick to establish an approximation of a log response using a linear pot and a single fixed resistor that’s good for about two decades - provided that the source and load impedances are appropriate to prevent undesirable attenuation at full volume.

One has to build a digital 90 degrees phase splitter circuit giving an in-phase (LO_I) and a quadrature phase (LO_Q) square LO signals phased out 90° one to each other. Among the following 4 circuits, there is one which is not performing that role.

Question: can you localize it and tell why?

1. With a 10K Ohm linear pot what is the value of the parallel fixed resistor R? to establish 10% attenuation at 50% rotation:
a. assuming zero source and infinite load impedance?
b. assuming 100 Ohms source and 10K Ohms load impedance?

2. There is no voltage attenuation for 1 a. at full volume, but what is the voltage attenuation at the load at full volume for 1b?

Good luck and try to be among the first ones!

KCC's Quizzes AQQ294 about a digital phase splitter design

KCC — Fri, 14 Nov 2025 08:31:48 GMT

1. Quote of the month: "I've learned that people will forget what you said, people will forget what you did, but people will never forget how you made them roll their eyes" - Robin Williams

2. New quiz of the month: AQQ294 about a digital phase splitter circuit

Question: can you localize it and tell why?

Good luck and try to be among the first ones!

KCC's Quiz AQQ293 about finding the cat

KCC — Wed, 15 Oct 2025 14:56:50 GMT

1. First, the quote of the week: "The best measure of a man's honesty isn't his income tax return. It's the zero adjust on his bathroom scale" - Unknown

2. New challenge with AQQ293 about finding the cat in the right box (the cat is well alive, it is NOT the famous Schrödinger's cat!)

Good luck and try to be among the first ones!

P.S. Please forward such quizzes to friends and colleagues who want also to "relax" their brains...

KCC's Quizzes AQQ292 about weighing using 2-plates scale

KCC — Tue, 30 Sep 2025 16:28:58 GMT

1. First, the quote of the week: "Some people create their own storms and then get mad when it rains" - Unknown

2. New challenge with AQQ292 about using a two-plates scale.

This is a kind proposal from a frequent participant: Herman Neufeld, Analog & Mixed Signals Specialist):

You are asked to design a two-dish scale that weighs amounts of a substance from 1 to 40 grams in integer amounts.

Hence your task is to determine:

What is the minimum number counterweights you need?
What are the weigh values of these counterweights?

These, in order to weigh this substance,

Good luck and try to be among the first ones!

P.S. Please forward such quizzes to friends and colleagues who want also to "relax" their brains...

KCC's Quizzes AQQ291 about counting number of ducks

KCC — Fri, 12 Sep 2025 19:11:29 GMT

1. First, the quote of the week: "Common sense is like deodorant. The people who need it most never use it" - Unknown

2. New challenge with AQQ291 about counting number of ducks carefully (there is no trap in this quiz...)

Source: MindYourDecision 7 puzzles that will test your mental skills

Test your eyes! How many ducks are shown in the above figure

Good luck and try to be among the first ones!

KCC's Quizzes AQQ290 about a triangle coming from the Hell

KCC — Fri, 22 Aug 2025 09:10:50 GMT

So, after a long (and deserved) summer vacation, we can suppose your brain is now fully energized and ready to tackle complex problem!

OK, I know the 2 famous laws about vacations!

1. Vacations are always too short (even if you had 4 weeks)!

2. They always occur in wrong moments (i.e. you were disturbed by any kind of urgencies).

1. First, the quote of the week: "People often say that motivation doesn't last. Well, neither does bathing - that's why we recommend it daily" - Zig Ziglar

Source: encrypted-tbn0.gstatic.com/images

2. New challenge: it's a geometry problem, about a triangle that comes from hell... Be careful, there is a trap...

A right triangle has a hypothenuse of 10 cm and an altitude to the hypothenuse of 6 cm.

Question: What is the area of the triangle ABC?

Good luck! And try to be among the first ones!

Also, don't hesitate to share such quizzes with colleagues or friends!

KCC's Quizzes AQQ289 about a pipeline Analog-to-Digital Converter

KCC — Mon, 28 Jul 2025 19:49:02 GMT

1. First a funny quote to start the week-end: "Coworkers are (sometimes) like Christmas lights. They hang together, half of them don't work and the other half aren't so bright" anonymous

2. New quiz AQQ289 about a Pipeline ADC:

Sorry for our non-electronic colleagues, but this one is a tough one...

Here is a block diagram of a 3-stages pipe line ADC.

With Vref = 5 volt and Vin = 2 volt, fill-in the various voltages observed at various nodes.

In particular, indicate the status of the bits B2, B1 and B0 at the end of the third active clock.

It is assumed here the components used (S/H, subtractor, amplifier, mux, comparator are all ideal (i.e. zero delay, no offset, no loss)

Good luck, and try to be among the first ones!

KCC's Quizzes AQQ288 about an amazing Equations System

KCC — Wed, 09 Jul 2025 16:29:40 GMT

1. First, the quote of the week: "The chief function of the body is to carry the brain around" - Thomas A. Edison

2. And here is the new challenge:

a*b = k

b*c = 2*k

c*a = 3*k

We have a set of 3 equations with 3 unknowns a, b and c.

k is an adjustable parameter.

Question:

Find all the values k that give positive integer solutions for a, b and c.

KCC's Quizzes AQQ287 about throwing 3 dice

KCC — Thu, 26 Jun 2025 09:38:21 GMT

1. Quote of the week:"The first five days after the wekend are always the hardest" - unknown

Source: Happy Weekend - Frohes Wochenende - Notiz mit einer Kaffeetasse - Kostenloses Foto auf ccnull.de / ccby.de

2 Our new challenge AQQ287 about throwing 3 dice

Source: upload.wikimedia.org/.../640px-160327_White_dice_09.jpg

The game consists to throw 3 dice and observe the sum S of the 3 top faces. We note P(S) the probability to obtain a sum S.

Questions:

1. For which value of S, the probability P(S) is maximum?

(Example: for 2 dice, S=7 occurs 6 times giving P(7)=0.167 which is the maximum we can get)

2. Same question as above but in a game with n number of dice.

Good luck and try to be among the first ones!

Also, please forward those quizzes to friends or colleagues who might be interested on such brainstorming!

KCC's Quizzes AQQ286 about Right Labels on the Right Boxes containing colored balls

KCC — Mon, 02 Jun 2025 11:28:31 GMT

1. Quote of the week: "Knowledge is knowing a tomato is a fruit. Wisdom is not putting it in a fruit salad" - unknown

Sources:

commons.wikimedia.org/.../index.php

https://commons.wikimedia.org/wiki/File:Tomato_je.jpg

2. New quiz to shake your brain... AQQ286 about putting right labels on right boxes containing colored balls

Good luck and try to be among the first ones!

Please forward the quizzes to friends or colleagues who can be interested in such challenges!

KCC's Quizzes AQQ285 about analog voltmeter expertise

KCC — Thu, 24 Apr 2025 14:29:11 GMT

1. Quote of the week: "If you think nobody cares if you're alive, try missing a few loan payments" - unknown

Source: Wikimedia

2. New quiz AQQ285 about the analog voltmeter expertise

We are back to our fundamental area: electronics...

Sources:

https://upload.wikimedia.org/wikipedia/commons/0/01/Galvanometer_scheme.svg

https://cdn2.picryl.com/photo/2015/12/24/spiegelskala-1-b45d8a-1024.JPG

We all remember from our first electronic lab, the use of analog multimeters to measure voltages, currents or resistances.

They are based on the galvanometer invented by d’Arsonval in which the interaction of a current (to be measured) with a permanent magnetic field moves a needle in front of graduated scales.

Due to mechanical inertia, the current measured is only sensitive to its average value.

Therefore measuring AC signals, like for example pure sinewaves, will indicate zero normally. Multimeters overcome this by rectifying the AC signal before to be measured.

The average value obtained is somehow fake since the original signal has been altered. However, such biased measure can reflect the RMS value of the signal.

This is why a second scale called “AC” mode, usually flagged in red, is calibrated to give the RMS value. However, such scale is only valid for pure sinewaves.

Questions:

1. That “AC” scale is slightly different vs the “DC” scale. The factor is around 1.11

How is it determined?

2. With the same voltmeter defined above, if you enter the following periodic signal, what are you going to read in the AC scale?

Good luck and try to be among the first ones...

P.S. As usual, please spread the quizzes among your friends and colleagues!

KCC's Quizzes AQQ284 about a ladder on a wall

KCC — Wed, 09 Apr 2025 13:06:46 GMT

1. Quote of the week: "My mind is like my web browser. 19 tabs are open, 3 are frozen and I have no idea where the music is coming from." - unknown

2. New quiz AQQ284 about a ladder on a wall puzzle ( a kind proposal from ALodwig607 - many thanks to him!):

A 10m ladder (=green line) leans at a wall (blue) and just touches a 1x1x1m box (red) that sits at the bottom of that wall. Wall and floor are of course 90°.

Question: How high H is the upper end of the ladder above the floor?

This is not an easy one....

Good luck and try to be among the first ones...

P.S. As usual, please spread the quizzes among your friends and colleagues!

KCC's Quizzes AQQ283 about Weighting Alphabetic Letters

KCC — Thu, 27 Mar 2025 10:41:41 GMT

1. Quote of the week: "Customers are like teeth. Ignore them and they'll go away" - Jerry Flanagan

Source: https://source.roboflow.com/A93JwBkvTQWfUenUZzdVjMVkIh33/3jgAFSPcyf0GIvIvn0cq/original.jpg

2. New challenge: AQQ283: Weighting alphabetic letters

A certain weighting coding is associated to each alphabetic letters in the following sequence:

A = 1

B = A+1

C= A+B+1

D= A+B+C+1

Etc…

What will be the value for Z?

Good luck and try to be among the first ones!

KCC's Quizzes AQQ282 about probability of finding people in a room

MatAEM — Fri, 21 Mar 2025 18:10:25 GMT

My answer is:

A:50

B:80

C:99

99+1

stevekennedyuk — Fri, 21 Mar 2025 15:01:48 GMT

to get the supervisors to 2% remove 49 workers.

5% remove 79 workers

100% remove 99 workers

KCC's Quizzes AQQ282 about probability of finding people in a room

KCC — Thu, 13 Mar 2025 13:32:34 GMT

1. Quote of the week: "By all means let's be open-minded, but not so open-minded that our brains drop out" - Richard Dawkins

2. Quiz AQQ282: Probabilities find people in a room (an original idea proposed by our colleague Cosimo CARRIERO, key account manager ADI Italy

Good luck, and try to be among the firsts!

Please spread those quizzes to colleagues and friends (1) Add Discussion - Quizzes - Logic Lounge - EngineerZone

KCC's Quizzes AQQ281 about volume of a perforated sphere

KCC — Thu, 27 Feb 2025 17:30:34 GMT

1. Quote of the week: "People wait all week for Fridays, all year for summer, all life for happiness" - Raimonda B.

2. Quiz AQQ281: volume of a perforated sphere. This very interesting challenge came from Ian Stewart and Daniel TheGreat (a frequenct participant to our quizzes...). Thanks to them!

A copper sphere has been fully perforated in its center by a right cylinder of height h.

Only h is known and is equal to 1 meter (cylinder radius r and sphere radius R are unknown).

Question: what is the volume of copper present in that structure?

Good luck and try to be among the first ones!

Please spread those quizzes to colleagues and friends (1) Add Discussion - Quizzes - Logic Lounge - EngineerZone

KCC's Quizzes AQQ280 about a relaxation oscillator with a double wipers potentiometer

KCC — Mon, 17 Feb 2025 18:08:47 GMT

1. Quote of the week: "Whatever you do, always give 100%. Unless you're donating blood" - Bill Murray

2. New quiz AQQ280:

The circuit here below is a relaxation oscillator using a double wipers potentiometer.

The opamp is considered ideal (i.e. infinite open loop gain, infinite input impedances, zero output impedance).

Questions:

What’s the frequency at Vout for a = 1/3 and b=2/3?
Same question as above but for a=10% and b=90%
What happens (i.e. Vout) if the 2 inputs of the MUX are swapped (i.e. a selected when S=1 and b selected when S=0) ?

Good luck and try to be among the first ones!

If you know friends or colleagues who should participate to the quiz, please let them know ((3) Add Discussion - Quizzes - Logic Lounge - EngineerZone) !

KCC's Quizzes AQQ279 about smart computing

KCC — Wed, 05 Feb 2025 17:20:56 GMT

1. Quote of the week: "One advantage of talking to yourself is that you know at least somebody's listening" - Franklin P. Jones

2. New challenge in AQQ279 about a smart computing puzzle:

Knowing that:

X = 1³ + 2³ + 3³ + 4³ +… + 11³ + 12³ = 6084

Question:

What is the value of:

Y = 2³ + 4³ + 6³… + 22³ + 24³

^{Good luck! and try to be among the first ones!}

^{P.S. Don't forget to spread those quizzes around you!}

KCC's Quizzes AQQ278 about an integrated Resistor

KCC — Tue, 21 Jan 2025 18:16:00 GMT

1. Quote of the week: "To succeed in life, you need three things: a wishbone, a backbone , and a funny bone" - Reba McEntire

2. The new quiz: AQQ278 about an integrated resistor:

Good luck and try to be among the first ones!

And, don't forget to help me by letting know your friends and colleagues about those quizzes!

KCC's Quizzes AQQ277 about a wrong digital design

KCC — Wed, 08 Jan 2025 15:16:05 GMT

* Quote of the week: "Never insult an alligator until after you have crossed the river" - unknown

* New Quiz AQQ277 about a digital design error:

An unskilled (it's not you) digital designer has to build a circuit that materializes the here above truth table.

He uses the Karnaugh table to generate and simplify the circuit as much as he can.

But obviously he made some mistakes because the circuit does not correspond to the truth table.

Questions:

Can you detect where the error(s) have been introduced?
What is your (correct) solution (it’s possible to get a circuit with only 2 simple gates)

Good luck! And try to be among the first ones (i.e. goodies are associated!)

And, if you know friends or colleagues who deserve to participate in these quizzes as well, tell them!

KCC's Quizzes AQQ276 about animals weights

KCC — Fri, 13 Dec 2024 18:41:50 GMT

1. Quote of the week:

"Good judgment comes from experience, and experience comes from bad judgment" - Rita Mae Brown

2. New challenge (and this one is a kind proposal of our colleague Rajesh Kumar, Snr Layout Designer at ADI India:

A dog, kat and rat have been weighted two by two.

Question:

What is the weight of each animal?

Good luck! And try to be among the first ones!

P.S. Please forward those quizzes to friends and colleagues!