Intermittent Oscillation Circuit Analysis

1. Self-excited intermittent oscillation circuit

　　Figure 1 (a) is a self-excited intermittent oscillation circuit. When the circuit is powered on (t=to), the current flows through the primary of the transformer to the collector, generating an induced voltage ui and a secondary induction voltage u2 (u1 is positive at the top and negative at the bottom, and u2 is positive at the bottom and negative at the top). U2 increases ub and ui, thus causing an "avalanche" positive feedback:

　　As a result, BG is saturated, ic increases linearly with time, u2 charges C, and ub decreases continuously until BG exits saturation (t-t1), and another "avalanche" positive feedback begins:

　　As a result, BG is cut off, ic=0o, C is discharged, ub voltage increases, and positive feedback is caused. In this way, BG works intermittently. The changes of various waveforms are shown in Figure 1 (b).

　　Figure 1. Self-excited intermittent oscillation circuit

　　2. Separately excited intermittent oscillation circuit

　　Figure 2 is a separately excited intermittent oscillation circuit. Since the bias pressure is zero, it can only work by external triggering. When there is no triggering effect, BG is cut off, and the negative trigger pulse is sent to the collector of BG through C and D1. The feedback process is the same as above.

　　Figure 2: Separately excited intermittent oscillation circuit