Regeneration analysis of junction transistor multivibrators

AN IMPORTANT aspect of transistor switching and pulse circuits is the exact manner in which the transistor switches from one state to another. Generally one state will involve transistor operation in or near saturation and the other state will involve transistor cutoff. For simple circuits, such as elementary pulse amplifiers, the switching action is under direct control of the input and is readily understandable.1 The situation is not as simple for relaxation type of circuits such as multivibrators, flip-flops, and blocking oscillators. For these circuits, the input serves as a trigger to raise the circuit into an unstable region of operation. The instability is due to a positive feedback circuit arrangement, and the regenerative process which results produces the change of state of the transistors.