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The Hi-pot Test

The hi-pot test is another safety subject of which few of us feel comfortable that we are in control. What is the purpose of the hi-pot test, and what hazard does it address or obviate? First, each of the st... Read More...
1409 C2 TS fig1

Characteristics of Air as an Insulator

A few months ago, we built a clear plastic box containing a four-inch square steel plane, a two-inch diameter steel sphere, and a micrometer drive to precisely adjust the distance between the plane and the sphe... Read More...
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Thermocouples and Temperature Measurement

One of our members suggested I write about thermocouples and temperature measurement. Textbooks have been written on this subject; I can only give a broad overview of the subject. Since temperature meaurement i... Read More...
1407 TS fig1

The Hazards of Multiple Grounding

One of my colleagues has a desk drawer full of I/O boards that have been burned quite severely. Why did they burn? The I/O boards are in energy-limited SELV circuits. There should be no possibility of fire. ... Read More...
1406 TS fig1

Resistor Value for Measuring Leakage Current

Furor and controversy are words which describe the process by which standards committees decide the value of the resistor in the leakage current measuring network. However, the different specified resistor values create no more than a 6.25% error for the value of the leakage current.