Figure 5-12 shows a simple circuit that can be used to detect the interruption of a light

Question:

Figure 5-12 shows a simple circuit that can be used to detect the interruption of a light beam. The light is focused on a phototransistor that is connected in the common-emitter configuration to operate as a switch. Assume that the latch has previously been cleared to the 0 state by momentarily opening switch SW1, and describe what happens if the light beam is momentarily interrupted.

Figure 5-12

+5 V + Vo +5 V S R SW1 Q Alarm