Regarding Component tester socket in Oscilloscope

[savvej]

The oscilloscope at our basic electronics lab has a oscilloscope with component tester socket.Now when we insert a diode,resistor or zener diode it shows the respective V-I characteristics on the oscilloscope screen.
But when we checked a capacitor or inductor it showed an ellipse.
Can anyone comment on why ellipse is displayed on the CRO screen?

 

[crutschow]

If you remember your circuit analysis, inductors and capacitors have the current and voltage out-of-phase (current leads the voltage for a capacitor and lags the voltage for an inductor). That generates the ellipse.

 

[MikeMl]

The oscilloscope at our basic electronics lab has a oscilloscope with component tester socket....

It is called a "curve tracer". It basically plots current on the vertical axis vs voltage on the horizontal axis as voltage is swept from zero to +-max voltage. More advanced models include a current/voltage step generator synchronized with the voltage sweep, so that the transfer characteristics of Bipolar and Field Effect Transistors can be plotted.

 

[BeeBop]

Mike, I could be mistaken, but think he did mean component tester (like the Huntron Tracker 2800 and 2800S - Component level Troubleshooting for the benchtop,) rather than curve tracer.

OK, still a curve tracer: "The Huntron Tracker series of in-circuit component testers are specialized curve tracers. You could get the basic I-V plot for a component using a standard semiconductor curve tracer."