LearnEMC @LearnEmc

LearnEMC helps companies build the in-house expertise they need to ensure their products will meet electromagnetic compatibility requirements. LearnEMC.com Stoughton, WI Joined March 2017

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LearnEMC @LearnEmc

10 hours ago

EMC Question of the Week: A good rule of thumb for ensuring that crosstalk between microstrip traces is -20 dB or lower is to maintain a spacing that is at least three times the trace a) width b) length c) height d) thickness. Answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

a week ago

EMC Question of the Week: At 100 MHz, a tinted window (εr = 8, thickness = 3 mm) has a plane wave shielding effectiveness of approximately a) 0 dB b) 2 dB c) 4 dB d) 6 dB Answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

2 weeks ago

EMC Question of the Week: How many fundamental EM coupling mechanisms are there? a) two b) three c) four d) more than four Answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

3 weeks ago

EMC Question of the Week: In an EMI test, one device produces a 40 dB(μV/m) field and another 34 dB(μV/m). What is the measured field strength from both devices? a) 41 dB(μV/m) b) 43.5 dB(μV/m) c) 71 dB(μV/m) d) 74 dB(μV/m) Full question and answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

4 weeks ago

EMC Question of the Week: Which of these currents is primarily responsible for radiated emissions from cables? a) odd mode b) even mode c) differential mode d) common mode Answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

a month ago

EMC Question of the Week: Which material property is primarily responsible for the loss in a high-frequency ferrite bead or ferrite core used for EMI suppression? a) complex permittivity b) complex permeability c) conductivity d) eddy currents Answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

2 months ago

EMC Question of the Week: Which of the following is NOT one of Maxwell's equations? a) Ohm's Law b) Gauss's Law c) Ampere's Law d) Faraday's Law Answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

2 months ago

EMC Question of the Week: Which plot is most helpful for predicting common-mode choke performance? a) attenuation vs. frequency b) impedance magnitude vs. frequency c) complex impedance vs. frequency d) complex core permeability vs. frequency Answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

2 months ago

EMC Question of the Week: The resolution bandwidth of a signal sampled in the time-domain and displayed in the frequency domain is determined by the a) acquisition time b) sampling rate c) windowing function d) scope bandwidth Answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

2 months ago

EMC Question of the Week: The length of a two-terminal surface-mount component is always the a) longest dimension b) longest dimension that is not the height c) distance between end caps d) distance between outer edges of end caps Answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

3 months ago

EMC Question of the Week: The sum of the currents flowing into a circuit node is essentially zero as long as we can neglect the a) parasitic inductances b) parasitic capacitances c) parasitic resistances d) laws of physics Answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

3 months ago

EMC Question of the Week: If a board-mounted common-mode choke connects directly to the connector pins, with no Y-capacitors in between, then the common-mode choke should be a) bifilar wound b) low loss c) lossy d) removed Answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

3 months ago

EMC Question of the Week: For a signal propagating in a transmission line, what must remain constant to avoid reflections? a) the ratio of the voltage to the current b) the ratio of the E and H fields c) wire diameter d) propagation direction Answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

3 months ago

EMC Question of the Week: A shielded cable with twisted-wire-pairs carrying high-frequency signals connects to a circuit board mounted in a plastic enclosure with no metal chassis. How and where should the shield be connected? Full question and answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

4 months ago

EMC Question of the Week: The main purpose of a shielded cable's drain wire is to provide: a) mechanical strength b) a path for low-frequency current c) an earth ground connection d) a connection to the connector shield. Answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

4 months ago

EMC Question of the Week: A stripline trace in an FR-4 dielectric forms a transmission line with a capacitance per unit length equal to 1.5 pF/cm. What is the characteristic impedance of that transmission line? Full question and answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

4 months ago

EMC Question of the Week: A microstrip trace pair has a differential-mode impedance of 100 Ω and a common-mode impedance of 40 Ω. What termination resistances match both the common-mode and differential-mode propagation. Full question and answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

4 months ago

EMC Question of the Week: Which of these RC low-pass filter layouts is most likely to help this product meet its EMC requirements? Full question and answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

4 months ago

EMC Question of the Week: The primary purpose of printed circuit board shields is to reduce a) conducted coupling b) radiated coupling c) near-field coupling d) power bus noise Answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

5 months ago

EMC Question of the Week: The yellow component in the image below is a a) ceramic capacitor b) tantalum capacitor c) TVS diode d) crystal oscillator Answer at learnemc.com/emc-question-o….