Question of the Week - Answer 231120https://learnemc.com/qotw-231120

EMC Question of the Week: November 20, 2023 A circuit board trace routed over a return plane can be a significant source of radiated emissions if it is not matched is not electrically short has 90o corners none of the above Answer The best answer is...

Question of the Week - Answer 240304https://learnemc.com/qotw-240304

EMC Question of the Week: March 4, 2024 A current probe with a 10-Ω transfer impedance is connected to a 50-Ω EMI test receiver in peak detection mode. A narrow band peak is observed with an amplitude of 54 dB(μV). What is the rms value of the measured...

Question of the Week - Answer 200127https://learnemc.com/qotw-200127

EMC Question of the Week: January 27, 2020 A key advantage of moving to higher switching frequencies in switch-mode power converters is improved efficiency lower EMI smaller components all of the above Answer The best answer is "c". For a given supply...

Question of the Week - Answer 220808https://learnemc.com/qotw-220808

EMC Question of the Week: August 8, 2022 To ensure compliance with EMC requirements, most low-speed digital I/O traces longer than a few centimeters that connect to a high-speed microcontroller should have series resistors controlled impedances matched...

Question of the Week - Answer 220711https://learnemc.com/qotw-220711

EMC Question of the Week: July 11, 2022 Which of the following is often employed in sources of intentional electromagnetic interference (IEMI)? Marx generator Van de Graaff generator Tesla coil Flux capacitor Answer The best answer is “a.” A Marx...

Question of the Week - Answer 210301https://learnemc.com/qotw-210301

EMC Question of the Week: March 1, 2021 Which 50-Ω coaxial connector type would never be secured using a torque wrench? BNC TNC N-Type SMA Answer The best answer is “a.” BNC connectors are secured with a quarter-turn of the coupling nut on the outer...

Question of the Week - Answer 230529https://learnemc.com/qotw-230529

EMC Question of the Week: May 29, 2023 To reduce the crosstalk between signals on microstrip lines, guard traces should be shorted at both ends matched at both ends floated at one end avoided Answer The best answer is “d.” Guard traces routed between...

Question of the Week - Answer 200224https://learnemc.com/qotw-200224

EMC Question of the Week: February 24, 2020 An important advantage of pseudo-differential signaling compared to differential signaling is that it doesn't require a ground conductor twisted wire pair balun DC bias voltage Answer The correct answer is...

Question of the Week - Answer 210322https://learnemc.com/qotw-210322

EMC Question of the Week: March 22, 2021 What property of a two-conductor transmission line is strongly correlated to the radiated emissions from that transmission line? characteristic impedance electrical balance differential-mode voltage common-mode...

Question of the Week - Answer 200120https://learnemc.com/qotw-200120

EMC Question of the Week: January 20, 2020 In which application is active noise cancellation often a cost-effective alternative to shielding? low-frequency magnetic field interference low-frequency electric field interference interference from...

Question of the Week - Answer 210607https://learnemc.com/qotw-210607

EMC Question of the Week: June 7, 2021 The first (lowest) resonant frequency of a 40-cm x 16-cm x 38-cm rectangular metal enclosure is below 10 MHz approximately 380 MHz approximately 540 MHz above 1 GHz Answer The best answer is “c.” The resonance...

Question of the Week - Answer 200203https://learnemc.com/qotw-200203

EMC Question of the Week: February 3, 2020 Which shielding material is unlikely to be a good choice for helping to meet a conducted emissions specification? aluminum copper mumetal all of the above Answer The best answer is "c". Mumetals are...

Question of the Week - Answer 211115https://learnemc.com/qotw-211115

EMC Question of the Week: November 15, 2021 Electrolytic capacitors have a relatively large capacitance for a given package size compared to ceramic capacitors making them well-suited for use as, X-capacitors in AC power filters Y-capacitors in AC...

QOTW2https://learnemc.com/qotw2

EMC Question of the Week 2021 - 2024 Available Now! This book compiles every EMC Question of the Week published on the LearnEMC website from January 2021 through December 2024. There are 212 multiple-choice questions with the correct answer and a brief...

Question of the Week - Answer 200106https://learnemc.com/qotw-200106

EMC Question of the Week: January 6, 2020 Thyristors are generally ineffective for protecting against ESD transients, because they have too much capacitance can't handle the energy must be manually reset are too slow to turn on Answer The correct...

Question of the Week - Answer 220704https://learnemc.com/qotw-220704

EMC Question of the Week: July 4, 2022 In the United States, which products are typically subject to government electromagnetic immunity requirements? computing devices automotive electronics medical devices all of the above Answer The best answer is...

Question of the Week - Answer 240226https://learnemc.com/qotw-240226

EMC Question of the Week: February 26, 2024 At 1 GHz, a 1-volt input to a 25-meter cable produces a 100-mV output due to cable loss. What would the output voltage be if the cable length were 50 meters? 200 mV 100 mV 50 mV 10 mV Answer The correct...

Question of the Week - Answer 250512https://learnemc.com/qotw-250512

EMC Question of the Week: May 12, 2025 The yellow component in this figure is a ceramic capacitor tantalum capacitor TVS diode crystal oscillator Answer The correct answer is “b.” These yellow polarized capacitors often used for DC power bus decoupling...

Question of the Week - Answer 230918https://learnemc.com/qotw-230918

EMC Question of the Week: September 18, 2023 A 1-Gbps signal propagates from a single-ended source on a microstrip trace to a connector. Which cable option would be appropriate to convey this signal to another circuit board 1 meter away? twisted wire...

Question of the Week - Answer 200210https://learnemc.com/qotw-200210

EMC Question of the Week: February 10, 2020 HDMI, USB, LVDS, CAN and RS-485 are all communications interfaces that employ single-point grounds ring topologies coaxial cables differential signaling Answer The correct answer is "d". Each of these...

Question of the Week - Answer 210419https://learnemc.com/qotw-210419

EMC Question of the Week: April 19, 2021 The two identical components in the center of the figure are 0-Ω resistors inductors ferrite beads tantalum capacitors Answer The correct answer is “c.” The components labeled L26 and L27 are ferrite beads. It's...

Question of the Week - Answer 230320https://learnemc.com/qotw-230320

EMC Question of the Week: March 20, 2023 How many independent TEM modes (i.e., differential modes) can propagate in an unshielded wire harness with 4 wires? 2 3 4 5 Answer The best answer is “b.” A transmission line with N conductors can support N-1...

Question of the Week - Answer 220919https://learnemc.com/qotw-220919

EMC Question of the Week: September 19, 2022 Which device can be useful for determining whether a material is suitable for low-frequency (0-100 Hz) magnetic field shielding? ohm meter E-field meter magnetron permanent magnet Answer The best answer is...

Question of the Week - Answer 211004https://learnemc.com/qotw-211004

EMC Question of the Week: October 4, 2021 IBIS is a standard file format for characterizing a digital component's inputs and outputs power bus noise heat dissipation requirements conducted emissions Answer The correct answer is “a.” IBIS or...

Question of the Week - Answer 250609https://learnemc.com/qotw-250609

EMC Question of the Week: June 9, 2025 A circuit board trace embedded in an FR-4 (εr = 4.3) dielectric between two planes forms a transmission line with a capacitance per unit length equal to 1.5 pF/cm. What is the characteristic impedance of that...

Question of the Week - Answer 210104https://learnemc.com/qotw-210104

EMC Question of the Week: January 4, 2021 EFT/B is an acronym used to describe one form of electrical fast transient testing. The "B" in this acronym stands for buck back burst Class B Answer The correct answer is “c.” EFT test standards generally...

Question of the Week - Answer 220411https://learnemc.com/qotw-220411

EMC Question of the Week: April 11, 2022 A smart watch exhibits an audible hum when it's near AC power lines. Completely wrapping the watch in aluminum foil does not reduce the interference but placing the watch in a steel box does. The interference is...

Question of the Week - Answer 240923https://learnemc.com/qotw-240923

EMC Question of the Week: September 23, 2024 Which of the following is equivalent to 40 dB(μV/m)? 40 μV/m 40 dB 100 nA/m -80 dB(V/m) Answer The best answer is “d.” 40 dB(μV/m) is an electric field strength equal to 100 μV/m, which is 10‑4 V/m or -80...

Question of the Week - Answer 230626https://learnemc.com/qotw-230626

EMC Question of the Week: June 26, 2023 When referring to integrated circuit packages, QFN is an acronym for Quiet Fasteners Numbered Quality Four-sided Numbered Quick Fixed Normal Quad Flat No-Lead Answer The correct answer is “d.” QFN packaging for...

Question of the Week - Answer 201102https://learnemc.com/qotw-201102

EMC Question of the Week: November 2, 2020 A 10-cm x 10-cm printed circuit board has one high-speed switching device and closely spaced (

Bookshttps://learnemc.com/books

EMC Books EMC Question of the Week 2021-2024 This book is a collection of the LearnEMC EMC Questions of the Week from March 2021 through December 2024. EMC Question of the Week 2017-2020 This book is a collection of the LearnEMC EMC Questions of the...

QOTW - International Shippinghttps://learnemc.com/qotw-international-shipping

EMC Question of the Week - International Shipping Unfortunately, we are no longer able to ship this book directly to locations outside the United States due to the high probability of long shipping times or lost packages. People in countries serviced...

Thank You QOTWhttps://learnemc.com/thank-you-qotw

Thank You! Thank you for purchasing the book EMC Question of the Week 2017-2020. The book will be shipped by USPS priority mail within one business day of your order.