Clayton Grantham writes:
Some years ago, one of the fundamental electronic instruments was the laboratory curve tracer. A CRT display would sweep out terminal behavior (current versus voltage) from which you could derive mathematical models. Classic presentations of diodes, transistors, and other devices enlightened designers about linear and nonlinear operation. From the displays, you could determine the bias points for optimum design performance. Today, however, you rarely find the classic curve tracers in the lab. Instead, you find design-simulation software, such as Spice, that’s removed from hands-on, empirical analysis. Spice models now exist for almost all electronic components. Characterization analyzers still make the voltage-current measurements but not at the design-engineer level. Rather, departments are dedicated to characterizing processes and components and incorporating these characteristics into the simulated models. The low-cost circuit in Figure 1 allows you to return to the hands-on approach by using your PC as a limited curve tracer.
Trace voltage-current curves on your PC – [Link]