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 260525https://learnemc.com/qotw-260525

EMC Question of the Week: May 25, 2026 A 100-MHz sine wave is measured with a 50-Ω oscilloscope and displays a peak amplitude of 2.0 volts. The same signal measured on a 50-Ω spectrum analyzer should have a single narrow-band peak with an amplitude of...

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 191028https://learnemc.com/qotw-191028

EMC Question of the Week: October 28, 2019 Generally speaking, which type of signal should never be transmitted on a twisted wire pair? high-speed single-ended signals high-speed pseudo-differential signals 1 Gbps differential signals all of the above...

Question of the Week - Answer 190624https://learnemc.com/qotw-190624

EMC Question of the Week: June 24, 2019 The minimum risetime of lightning-induced pulses (as specified in lightning immunity standards such as IEC 61000-4-5) is on the order of picoseconds nanoseconds microseconds milliseconds Answer The correct answer...

Question of the Week - Answer 190701https://learnemc.com/qotw-190701

EMC Question of the Week: July 1, 2019 A time-domain reflectometer (TDR) is used to measure a transmission line’s impedance as a function of time frequency temperature location Answer The correct answer is "d". A TDR sends a voltage step signal down a...

Question of the Week - Answer 190729https://learnemc.com/qotw-190729

EMC Question of the Week: July 29, 2019 Which of the following materials could not exist in the real physical world? Flexicon (σ = 0.001 S/m, εr = 2, μr = 1) Plastipure (σ = 10-5 S/m, εr = 0.4, μr = 1) Magnemite (σ = 2x105 S/m, μr = 10,000) M-alloy (σ...

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 190128https://learnemc.com/qotw-190128

EMC Question of the Week: January 28, 2019 Gas discharge tubes are generally ineffective for protecting against ESD transients, because they have too much capacitance can't handle the energy are too slow to turn on all of the above Answer The best...

Question of the Week - Answer 190513https://learnemc.com/qotw-190513

EMC Question of the Week: May 13, 2019 If a 25 MHz sine wave with a peak amplitude of 2 volts is input to a spectrum analyzer, the amplitude of the harmonic at 25 MHz recorded by the analyzer should be 126 dB(μV) 123 dB(μV) 66 dB(μV) depends on the RBW...

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 180416https://learnemc.com/qotw-180416

EMC Question of the Week: April 16, 2018 Intentional transmitters that typically operate at ISM-band frequencies include, commercial AM and FM radio stations wireless microphones and garage door openers submarine telecommunication equipment none of the...

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 260413https://learnemc.com/qotw-260413

EMC Question of the Week: April 13, 2026 A wireless ESD wrist strap dissipates accumulated charge using ionization radiation thermal induction none of the above Answer The best answer is “d.” Wireless (or cordless) ESD wrist straps simply don't...

Question of the Week - Answer 190402https://learnemc.com/qotw-190402

EMC Question of the Week: April 2, 2019 A triboelectric series ranks materials based on conductivity affinity for moisture shielding effectiveness affinity for electrons Answer The correct answer is "d." When two dissimilar materials are in contact,...

Question of the Week - Answer 171023https://learnemc.com/qotw-171023

EMC Question of the Week: October 23, 2017 A significant advantage that carbon composition resistors have over metal film resistors is that carbon composition resistors, are cheaper have tighter tolerances are more resistant to voltage surges all of...

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 190218https://learnemc.com/qotw-190218

EMC Question of the Week: February 18, 2019 Another name for electric-field coupling is conducted coupling capacitive coupling inductive coupling radiated coupling Answer The correct answer is "b." There are exactly four EM coupling mechanisms, and...

Question of the Week - Answer 190909https://learnemc.com/qotw-190909

EMC Question of the Week: September 9, 2019 A 30-dB attenuator reduces the signal voltage by approximately a factor of 3 3.3 30 1000 Answer The correct answer is "c". Converting from decibels to a voltage ratio, 10 30 / 20 = 31.6 or working it in the...

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 171106https://learnemc.com/qotw-171106

EMC Question of the Week: November 6, 2017 The only EM coupling mechanism that can result in crosstalk at DC (0 Hz) is, common impedance coupling electric field coupling magnetic field coupling radiated field coupling Answer The correct answer is "a"....

Question of the Week - Answer 171016https://learnemc.com/qotw-171016

EMC Question of the Week: October 16, 2017 The main advantage that X7R capacitors have over NP0 capacitors is that X7R capacitors, can have higher nominal values for a given package size are more stable with temperature are more stable with applied...

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 190422https://learnemc.com/qotw-190422

EMC Question of the Week: April 22, 2019 Which of the following common EMC topologies can be modeled as a series RLC circuit? decoupling capacitors electrostatic discharge events radiating structures at resonance all of the above Answer The correct...

Question of the Week - Answer 190617https://learnemc.com/qotw-190617

EMC Question of the Week: June 17, 2019 HERO and HERF requirements are designed to prevent high intensity radio frequency fields from affecting helicopters communications equipment things that explode human tissue Answer The correct answer is "c". HERO...

Question of the Week - Answer 171120https://learnemc.com/qotw-171120

EMC Question of the Week: November 20, 2017 Another name for common impedance coupling is, electric field coupling magnetic field coupling conducted coupling radiated coupling Answer The correct answer is "c". Common impedance (or common resistance)...

Bookshttps://learnemc.com/books

illustrate how the various concepts presented are applied to actual electronic circuit boards and systems. 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 - Answer 191021https://learnemc.com/qotw-191021

EMC Question of the Week: October 21, 2019 On boards with closely spaced (

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 (

Question of the Week - Answer 170807https://learnemc.com/qotw-170807

EMC Question of the Week: August 7, 2017 On boards with closely spaced (

Question of the Week - Answer 190429https://learnemc.com/qotw-190429

EMC Question of the Week: April 29, 2019 Materials such as plastics with embedded carbon nanofibers can make better shielded enclosures than metallic enclosures because they absorb more power reflect more power transmit more power have no seams Answer...

Question of the Week - Answer 190408https://learnemc.com/qotw-190408

EMC Question of the Week: April 8, 2019 Normalized site attenuation measurements are performed to evaluate the integrity of semi-anechoic environments reverberation chambers TEM and GTEM cells filters Answer The correct answer is "a." Site attenuation...

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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...

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