What is an ohmmeter?
Ohmmeter is a device that measures the amount of electrical friction generated when electrons pass through the electrical conductor. Also known as electrical resistance, its value is expressed in the "OHM" units. This measurement is governed by the "ohm law", which states that the current passing through the electrical circuit is directly proportional to the amount of voltage developed. When this natural phenomenon is written as an algebraic equation, it looked like this: r = v/i, where r is resistance, V is a voltage and I represent a current. This illustration of the relationship between these values is attributed to German physics and 19th century teachers, Georg Simon Ohm.
The drive of how the ohmmeter works is very simple. First, the ohmmeter must be able to generate the internal stream flow; Therefore, it is supplied with its own battery. The device also consists of two wires from which resistance between them is measured. The red lead is connected to the Corodpit positive terminal of the tested electric unit, while the black is connected to the negative. As the current flows from the batteryIE and via the unit, the ohmmeter measures the voltage or resistance that occurs.
If it is open in the circuit, the result is called "infinite resistance" and is marked with a needle of the tool at the bottom left on the logarithmic scale. This may seem strange because most other electrical measuring devices are swinging right to indicate the maximum level. On the other hand, if there is no resistance, the ohmmeter gives the reading zero. However, if resistance is expected, then this reading suggests that it is short in the tested unit.
While the earliest device used only two wires, the next generation consisted of four. One pair directed the stream flow while the other measured resistance. The purpose of this improvement was to compensate for any scattering in the regulation of the voltage between the first two wires that could endanger accuracy, especially when attempting to measure very low resistance. Finally, a modern ohmmeter that dNES uses, provides digital reading much more accurate, which is a significant improvement compared to its analog predecessor.
Regardless of the analog or digital, the ohmmeter should never be connected to an electrical unit that has its own voltage source. For one thing, the tool is designed to measure resistance based on the flow of current produced by its own battery. Any interference from another current source undermines its function and creates false values. In addition, if the secondary voltage source is high enough, it can irreversibly damage the ohmmeter.