Use the Analog Discovery™ and a digital multimeter to explore a fundamental equation used in electric circuit analysis and design: Ohm's Law.
Apply a time-varying voltage to a resistor using the Analog Discovery™ waveform generator. We will use the Analog Discovery oscilloscope to measure the resulting current, and plot the voltage as a function of current. The resulting plot will show the resistor's voltage-current characteristic, or I-V curve.
Ohm's Law states that the voltage difference across a resistor is proportional to the current through the resistor. This topic page will guide the user through a set of problems to help understand how to apply Ohm's Law.
In this section, we will look at Ohm's law from the standpoint of a voltage-current relationship. This will provide some continuity with our presentation of voltage current relationships for other components, such as capacitors, inductors, diodes, and transistors later on.
In this exercise, we will be measuring the resistance of several resistors that all have the same nominal resistance in order to determine the actual resistor-to-resistor resistance variations.
We will use some basic statistical analyses in this section to examine measurement variations. Statistics are a way to quantify variations in results which are due to random effects—or minimize the significance of these effects on our final conclusions.
Measuring current directly tends to be tedious—you generally need to break open your circuit in order to insert the ammeter into the circuit. Voltage measurements tend to be considerably easier, so it is common to determine the current in a circuit by measuring the voltage across a known resistor and using Ohm's law to estimate the current through the resistor.