Hello I'm now studying current mirror and have a question about replacement of diode to transistor as shown in the attached image. The upper image is original current mirror circuit shown in study document. Collector current IC is very similar to current through Rbias thus current to load can be controlled by adjusting Rbias. Since this scheme requires prefect matching of saturation current between diode and transistor base-emitter junction, 2nd circuit is suggested (Let's focus left circuit) where diode is replaced to identical transistor in 1st circuit with base-collector wiring. This wiring ensures that collector-base voltage becomes zero and...It is wired for me as I have known that VEB typically 0.2 V in normal operation. (so called active mode maybe?) As base is very thin layer thus current can flows from emitter to collector via diffusion (not drift by voltage from base to collector) but...Is this normal condition? Does this wiring simply transform transistor to diode?