How do you reverse bias base collector junction?

To reverse bias a base-collector junction in a bipolar junction transistor (BJT), you need to apply a positive voltage to the collector relative to the base for an NPN transistor (or a negative voltage for a PNP transistor). This involves connecting the collector terminal to a higher potential and ensuring the base terminal is at a lower potential. As a result, the depletion region at the base-collector junction widens, preventing current flow between the collector and base. This condition is essential for transistor operation in certain configurations, such as in cutoff mode.