- Used as an additional resistor to extend the voltage range in a circuit, providing flexibility for experiments and measurements. - Serves as a source of electromotive force (emf) and provides the internal resistance necessary for measuring a power supply. - Enables verification of Ohm's law by incorporating it into a circuit and observing the relationship between voltage, current, and resistance. - Useful for measuring unknown resistance by integrating it into measurements where known values are used to determine an unknown value. Use scenarios - Educational labs: connect the resistor as an extra load to widen the voltage range available for experiments and to verify Ohm's law with real measurements. - Power supply testing: use the device to model a power supply under test by providing emf and internal resistance, allowing you to characterize the source. - Unknown resistor determination: place it in a circuit to help calculate an unknown resistance from measured voltages and currents.