Source: https://mokxi.com/learn/path/measurement-and-instruments Updated: 2026-11-11 All paths # Measurement and instruments How far to trust a reading: resolution and accuracy, meter loading, bandwidth and the x10 probe, triggering, counters, bus decoding, and an error budget for a real gauge. Arduino Uno R3 Free 7 lessons 6 h 4 chapters 2,343 XP Electrical ยท Intermediate +150 XP 0 of 7 done Start the course free Accuracy and resolution Lesson plan for teachers What you will build ## 3 projects, built step by step 7 lessons in 4 chapters, about 6 hours on a simulated Arduino Uno R3. Free, in your browser, every step checked by the simulator. Chapter 1 project ### Meter loading Two 1 megohm resistors should halve 5 V. The meter says otherwise, because the meter is a 10 megohm resistor in the circuit. Predict the error, prove it, and learn when to stop worrying about it. Open it in the simulator Chapter 2 project ### Triggering Why a scope trace stands still: a level and a slope. Set them on the scope, then write a trigger in code (slope, level and auto mode) and watch it behave exactly like the front panel. Open it in the simulator Chapter 3 project ### Logic analyzers One analyzer, two buses: decode SPI into a shift register, then move the probes and decode I2C into an expander, including the NACK of a chip that is not there. Open it in the simulator The map ## Chapter by chapter Each lesson opens when the one before it is done, and each chapter ends in a project. Chapter 1 ## The meter, honestly What the digits mean, and what the meter does to the circuit. Open 200 XP ### Accuracy and resolution A bench meter and an Uno read the same knob. Counts, digits and the 4.88 mV step a 10-bit converter cannot see inside, and why "how fine" and "how right" are different questions. 0 of 6 steps Start What is in it Project Locked 436 XP ### Meter loading Two 1 megohm resistors should halve 5 V. The meter says otherwise, because the meter is a 10 megohm resistor in the circuit. Predict the error, prove it, and learn when to stop worrying about it. 0 of 6 steps Chapter 2 ## The scope Bandwidth, the x10 probe and a trigger you write yourself. Locked 249 XP ### Probes and bandwidth Every instrument input is a low-pass filter. Find the corner of one with two AC meters, then build a x10 probe by hand and compensate it the way you tune a real one on the bench. 0 of 7 steps Project Locked 462 XP ### Triggering Why a scope trace stands still: a level and a slope. Set them on the scope, then write a trigger in code (slope, level and auto mode) and watch it behave exactly like the front panel. 0 of 7 steps Chapter 3 ## Counting and decoding Frequency, duty and the bytes on a bus. Locked 236 XP ### Frequency counters Count a 555 two ways, with a frequency counter and with a meter. Gate time and the last digit, duty cycle, and predicting a new frequency from the parts before you measure it. 0 of 6 steps Project Locked 498 XP ### Logic analyzers One analyzer, two buses: decode SPI into a shift register, then move the probes and decode I2C into an expander, including the NACK of a chip that is not there. 0 of 7 steps Chapter 4 ## Boss An error budget for a battery gauge, then calibrate it. Locked 262 XP ### Boss: an error budget A battery gauge reads 11.961 V on a 12.000 V supply. Find every millivolt: meter loading, resolution, resistor tolerance and the reference, then calibrate it and write the budget. 0 of 8 steps Syllabus ## Every lesson in the course All 7 lessons, in order, each with what it covers. Any of them opens in the editor right away. Chapter 1 ### The meter, honestly - Accuracy and resolution A bench meter and an Uno read the same knob. Counts, digits and the 4.88 mV step a 10-bit converter cannot see inside, and why "how fine" and "how right" are different questions. - Meter loading Two 1 megohm resistors should halve 5 V. The meter says otherwise, because the meter is a 10 megohm resistor in the circuit. Predict the error, prove it, and learn when to stop worrying about it. Chapter 2 ### The scope - Probes and bandwidth Every instrument input is a low-pass filter. Find the corner of one with two AC meters, then build a x10 probe by hand and compensate it the way you tune a real one on the bench. - Triggering Why a scope trace stands still: a level and a slope. Set them on the scope, then write a trigger in code (slope, level and auto mode) and watch it behave exactly like the front panel. Chapter 3 ### Counting and decoding - Frequency counters Count a 555 two ways, with a frequency counter and with a meter. Gate time and the last digit, duty cycle, and predicting a new frequency from the parts before you measure it. - Logic analyzers One analyzer, two buses: decode SPI into a shift register, then move the probes and decode I2C into an expander, including the NACK of a chip that is not there. Chapter 4 ### Boss - Boss: an error budget A battery gauge reads 11.961 V on a 12.000 V supply. Find every millivolt: meter loading, resolution, resistor tolerance and the reference, then calibrate it and write the budget. Kits ## Build it on your bench too Every lesson runs in the simulator with nothing to buy. When you want the real thing, these kits have the parts. Have a kit already? ### Find your kit Pick the starter kit you own and run every lesson in its manual with the same parts on the same pins. See every kit Questions ## About Measurement and instruments Is Measurement and instruments free? Yes. All 7 lessons of Measurement and instruments are free and run in your browser, with nothing to install and no parts to buy before you start. Do I need a real Arduino Uno R3? No. Every lesson runs on a simulated Arduino Uno R3 with its parts on the canvas, and the simulator checks each step as you go. When you want to build it for real, the same wiring and code work on a real board. How long does Measurement and instruments take? About 6 hours: 7 lessons in 4 chapters, each one a few short steps. Your progress is kept, so you can stop after any lesson and pick up where you left off. What will I build? Each chapter ends in a project that puts it together: Meter loading, Triggering and Logic analyzers. Where do I start? With "Accuracy and resolution", and each lesson builds on the one before it. New to circuits? Electronics basics is the course that starts from zero.