Address:  P. O. Box 1457, Los Gatos, CA 95031
 TEL:      800-323-3956/408-356-4186
 FAX:      408-358-3799
 Mobile:   408-858-4528
 URL:      www.dsmith.org
 Email:    doug@dsmith.org

   Seminar Equipment

My seminars include lots of experiments and demonstrations. The figure above shows some of the material that I bring. The boxes in the picture are full of cables, components, circuit boards, and other demonstration materials. I believe that a day or more of  just viewing overhead transparencies is rather dull and boring. I spend about half, or more, of the class time demonstrating the principles being discussed. Often the students will think up new experiments and we do them together in real time. This provides interest for the students and helps make learning easier and more fun.
 

    Measurement of Voltage Across Pigtail

One of the experiments, measurement of the voltage across a pigtail using a Balanced Coaxial Probe is shown above. The coax cable is carrying a 5 volt square wave and the resultant pigtail voltage is 1.5 volts peak. This voltage is shown in the seminar to cause the shield of the coax cable to radiate at nearly 40dB above the Class A CISPR limit at a little above 30 MHz. Note the current probes to the sides measuring common mode current. Both currents and the voltage across the pigtail are shown on the oscilloscope simultaneously and projected on a large screen for the students to see.