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

2 days ago

EMC Question of the Week: What can we conclude from the near-field probe measurement depicted in the photo that shows 40 dB(μV) peaks between 30 and 50 MHz? Full question and answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

a week ago

EMC Question of the Week: Which of the following is a visual aid that is useful for analyzing certain transmission line problems in the frequency domain? a) Bounce Diagram b) Triboelectric Series c) Smith Chart d) Bob Smith Termination Answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

2 weeks ago

EMC Question of the Week: A shielded twisted pair connects a small sensor board to a controller board. The sensor board has a plastic enclosure. How and where should the cable shield be connected? Full question and answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

3 weeks ago

EMC Question of the Week: A 1.0-volt, 100-Mbps, single-ended signal driver sends a signal to a matched load on a 1-meter cable. Which of the cable options in the figure is least likely to cause a radiated emissions problem? Answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

4 weeks ago

EMC Question of the Week: Class II ceramic capacitors (e.g., X7R) are well-suited for a.) DC power bus decoupling b.) AC power bus decoupling c.) high-pass filtering d.) none of the above Full question and answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

a month ago

EMC Question of the Week: At 60 Hz, aluminum foil can effectively shield a.) electric fields b.) magnetic fields c.) both of the above d.) none of the above Full question and answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

a month ago

EMC Question of the Week: How fast can you draw charge from two parallel planes separated by a distance of 0.25 mm when they are initially charged to 1 volt? Full question and answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

2 months ago

EMC Question of the Week: Within the first 200 ps of a sudden demand for current to the BGA in the figure below, where is most of the current coming from? a.) C1 b.) C2 c.) C1 and C2 equally d.) the plane capacitance Answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

2 months ago

EMC Question of the Week: Assuming the product meets its EMC requirements, this PCB layer is almost certainly a layer devoted to a.) high-speed signals b.) power distribution c.) RTN d.) GND Answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

2 months ago

EMC Question of the Week: The initial spike from an ESD simulator discharged into a calibration target is primarily due to the a.) simulator's capacitor b.) simulator's switch c.) simulator's self-capacitance d.) target's center plate Answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

3 months ago

EMC Question of the Week: Which output in the figure corresponds to the measured voltage from a small 15-nH loop placed over a circuit board trace. The trace carries a current that looks like a 250-MHz square wave. Answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

3 months ago

EMC Question of the Week: A 1-Gbps signal is routed on a trace that is 0.25 mm above the return plane. This trace should normally have a a.) balanced termination b.) coplanar ground c.) controlled impedance d.) all of the above Full question and answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

3 months ago

EMC Question of the Week: A plane wave is incident on long parallel wires that have different diameters. Which of the following statements is correct? a.) ICM = I1 + I2 b.) IDM = 0 c.) VDM = 0 d.) all of the above Full question and answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

3 months ago

EMC Question of the Week: In order to filter the common-mode power bus noise effectively, which of the components shown in the schematic must be eliminated? a.) L2 b.) L3 c.) CX1 and CX2 d.) CX4 and CX5 Answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

4 months ago

EMC Question of the Week: Small unconnected copper dots or diamonds on the outer layers of a printed circuit board are an example of a.) ground fill b.) via stitching c.) guard posts d.) thieving Answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

4 months ago

EMC Question of the Week: What determines the location of the nulls in the (sin x)/x shape in the plot below? a.) transition time b.) duty cycle c.) fundamental frequency 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 sine wave has a peak amplitude of 2.0 volts on a 50-Ω scope. The same signal on a 50-Ω spectrum analyzer would be a narrow-band peak with an amplitude of a.) 6 dB(μV) b.) 120 dB(μV) c.) 123 dB(μV) d.) 126 dB(μV) Answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

4 months ago

EMC Question of the Week: One advantage of routing signals on microstrip trace pairs as opposed to stripline trace pairs is that microstrip trace pairs generally a.) radiate less b.) take up less space c.) have better balance d.) have lower loss Answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

4 months ago

EMC Question of the Week: Differential trace pairs on the outer layer of a printed circuit board 0.25 mm over a solid copper plane should generally a.) be tightly coupled b.) be length matched c.) have coplanar ground d.) all of the above Answer at learnemc.com/emc-question-o….

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LearnEMC @LearnEmc

5 months ago

EMC Question of the Week: If a digital signal trace extends a distance that exceeds its "critical length," it's generally necessary to a.) slow the transition time b.) provide a matched termination c.) either (a.) or (b.) d.) none of the above Answer at learnemc.com/emc-question-o….