When testing between the source and drain of an N channel JFET using the R x 100 range, what should the readings indicate?

When testing between the source and drain of an N-channel JFET using the R x 100 range, the correct readings should indicate equal resistance in both directions. This behavior is consistent with the characteristics of a JFET, which is designed to allow current flow from the drain to the source when the gate-source voltage is sufficiently negative, but does not conduct in the reverse direction due to the built-in potential barrier of the junctions. This leads to a symmetrical resistance reading when assessed with an ohmmeter, indicating that the device is not internally damaged or exhibiting abnormal behavior.

In contrast, an open reading in both directions would suggest a failure in the JFET, as it indicates a lack of connectivity. A variable reading in one direction might suggest faulty behavior or a damaged component, which would not be typical for a properly functioning JFET. Likewise, a short in both directions would indicate that there is a direct electrical connection without any resistance, typically pointing to a faulty device that has failed completely. Thus, equal resistance readings confirm that the JFET structure is intact and functioning correctly within its operational parameters.