The common base current gain a1 varies with the emitter current IA and a2 varies with IK (IA + IG). If the a gate current is applied, this would increase IA and directly lead to an increase in gain. Therefore a regenerative effect results. The removal of the gate current will not cause the device to turn off.
Active vs. passive voice. In a sentence written in the active voice, the subject of sentence performs the action. In a sentence written in the passive voice the subject receives the action. Active: The candidate believes that Congress must place a ceiling on the budget. Passive: It is believed by the candidate that a ceiling must be placed on the budget by Congress.
Active and Passive Voice in Writing. The choice between using the active or passive voice in writing is a matter of style, not correctness. However, most handbooks recommend using active voice, which they describe as more natural, direct, lively, and succinct. The passive voice is considered wordy and weak (except when used in cases above).