EDGE AS 1004149 - Caterpillar

The Ohm's Law solving circle is an easy way to remember how to solve any part of the equation. To use the solving circle (Illustration 2), cover any letter that you do not know. The remaining letters give you the equation for determining the unknown quantity. Voltage Unknown
Illustration 3 g01070300
In this circuit, the value of the source voltage is unknown. The resistance of the load is 2 ohms. The current flow through the circuit is 6 amps. Since the voltage is unknown, the equation to solve for voltage is current times resistance. So, multiplying 6 amps times 2 ohms equals 12 volts. Therefore, the source voltage in this circuit is 12 volts.Resistance Unknown
Illustration 4 g01070303
In this circuit, the value of the resistance is unknown. The current flow through the circuit is 6 amps and the source voltage is 12 volts. Since the resistance is unknown, the equation to solve for resistance is, voltage divided by current. So, 12 volts divided by 6 amps equals 2 ohms. Therefore, the resistance in the circuit is 2 ohms.Current Unknown
Illustration 5 g01070307
In this circuit, the current is unknown. The resistance of the load is 2 ohms and the source voltage is 12 volts. Since the current is unknown, the equation to solve for current is voltage divided by resistance. So, 12 volts divided by 2 ohms equals 6 amps. Therefore, the current flow in this circuit is 6 amps.Metric System of Measure
When you measure something, you find a number to express the size or the quantity of the item that is being measured. Numbers are used to express the results of simple calculations. In addition to using numbers, there is always a unit, or an expression to describe what the number means. In the study of electrical systems, the metric system is used for units of measurement.When you work in the metric system, there are only a few basic units that you need to be familiar with. Basically, you simply multiple or divide the basic unit by factors of 10 if you need a larger or smaller measuring unit. These factors of 10, or multiples of 10, have special names in the metric system. The names are used as prefixes. The names are attached to the beginning of the names of basic units.The following is an example of a metric prefix:
1500 Volts of electricity would be expressed metrically as 1.5kV.
The equation would be stated in power of 10 as 1.5 × 103 or 1.5 × 1000 = 1500.
The prefix k is equal to 1000, so the equation for 1500 volts is therefore stated as 1.5kV.Electrical applications and electronic applications work with either very large quantities or very small quantities. These quantities are expressed in metric prefixes.The metric system units make up an internationally recognized measuring system that is used throughout the world. The measuring system is called the International System of Units (SI). The following units are the most common units in the study of basic electrical theory: Mega (millions), Kilo (thousands), Milli (thousandths)