7–8 RESISTORS Resistors are one of the most common components found in electric circuits. The unit of measure for resistance is the ohm, which was named for the German scientist Georg S. Ohm. The symbol used to represent resistance is the uppercase Greek letter omega (V). Resistors come in various sizes, types, and ratings to […]
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Direct current fundamentals
Resistance : effect of temperature on resistance, the american wire gauge (awg) and stranded wire and cable
7–5 EFFECT OF TEMPERATURE ON RESISTANCE Resistance depends not only on length, area, and kind of material, but also on the temperature of the material. Figure A–2 of the Appendix gives two sets of values for the resistance of copper at two different temperatures. (The resistance values given for the higher temperature are used when […]
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Resistance : effect of temperature on resistance, the american wire gauge (awg) and stranded wire and cable
7–5 EFFECT OF TEMPERATURE ON RESISTANCE Resistance depends not only on length, area, and kind of material, but also on the temperature of the material. Figure A–2 of the Appendix gives two sets of values for the resistance of copper at two different temperatures. (The resistance values given for the higher temperature are used when […]
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Resistance : conductance vs. Resistance, resistivity of materials, length of a conductor and cross-sectional area (csa) of a conductor in circular mils.
Resistance 7–1 CONDUCTANCE VS. RESISTANCE It is well known that some materials, especially metals, permit electrical currents to easily flow through them. These materials, whose atomic structures readily provide free electrons, are referred to as good conductors. Silver is the best of such conductors, but it is seldom used because of its high cost. Copper […]
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Resistance : conductance vs. Resistance, resistivity of materials, length of a conductor and cross-sectional area (csa) of a conductor in circular mils.
Resistance 7–1 CONDUCTANCE VS. RESISTANCE It is well known that some materials, especially metals, permit electrical currents to easily flow through them. These materials, whose atomic structures readily provide free electrons, are referred to as good conductors. Silver is the best of such conductors, but it is seldom used because of its high cost. Copper […]
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Electrical quantity measurement : electrical meter connection and summary of electrical quantity measurement
6–4 ELECTRICAL METER CONNECTION The proper techniques of connecting electrical meters should be demonstrated and practiced in a laboratory setting. It is assumed that the reader has access to such facilities. However, the following guidelines are offered for your review and consideration: 1. When using multifunction test instruments, be sure that the test leads are […]
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Electrical quantity measurement : electrical meter connection and summary of electrical quantity measurement
6–4 ELECTRICAL METER CONNECTION The proper techniques of connecting electrical meters should be demonstrated and practiced in a laboratory setting. It is assumed that the reader has access to such facilities. However, the following guidelines are offered for your review and consideration: 1. When using multifunction test instruments, be sure that the test leads are […]
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Electrical quantity measurement : types of meters, ammeter and voltmeter scale interpretation and ohmmeter scale interpretation
Electrical Quantity Measurement 6–1 TYPES OF METERS The traditional meters have a pointer moving across the face of a scale (similar to the speedometer in many cars). Such instruments are classified as analog meters. Readings from analog meters are generally limited to three-digit accuracy. The third digit must often be estimated and, therefore, is uncertain. […]
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Electrical quantity measurement : types of meters, ammeter and voltmeter scale interpretation and ohmmeter scale interpretation
Electrical Quantity Measurement 6–1 TYPES OF METERS The traditional meters have a pointer moving across the face of a scale (similar to the speedometer in many cars). Such instruments are classified as analog meters. Readings from analog meters are generally limited to three-digit accuracy. The third digit must often be estimated and, therefore, is uncertain. […]
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Scientific notation and metric prefixes : significant digits, rounding off to three significant digits, metric prefixesand multiplication and division with powers of 10
5–4 SIGNIFICANT DIGITS Most practical calculations are generally limited to only three significant digits. What does this statement mean? An example will make this clear. Assume that some friends you know want to brag about the performance of their new automobile. They tell you that they clocked their speed at 104.6784935 miles per hour. (That […]
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