Interpreting Multimeter Readings
4. Understanding and Applying Your Measurements
You've connected the probes, and the multimeter is displaying a number. Great! But what does that number actually mean? It's not just a random squiggle on the screen. That number represents the DC voltage at that specific point in the circuit. Understanding how to interpret that reading is the next vital step.
First, pay attention to the units. The multimeter is likely displaying the voltage in Volts (V), but some multimeters might also display millivolts (mV). Remember that 1 Volt equals 1000 millivolts. So, a reading of 0.012V is the same as 12mV. Being mindful of the units is important, especially when working with sensitive circuits.
Next, consider the expected voltage. Do you know what the voltage should be at that point in the circuit? If you're measuring a 12V battery, and the multimeter reads 11.5V, that suggests the battery is slightly discharged. If it reads 8V, the battery might be nearly dead. Comparing the actual reading to the expected reading helps you diagnose problems.
Finally, remember that voltage is always relative. The multimeter measures the voltage difference between the two probe points. So, the voltage reading only makes sense in the context of the circuit. For example, a voltage reading of 5V might be perfectly normal in one part of a circuit, but a sign of trouble in another. The most important thing is to know what voltage you are expecting at that point, and verify that the reading is accurate and within tolerances.
The true value of knowing the DC voltage at various points in a circuit lies in its ability to help us diagnose the health of the circuit, and potentially track down components that may be failing. When in doubt, refer to a schematic or consult with someone with more experience.
