Retriggerable One Shot Timing — Pulse Extension A retriggerable one shot has nominal pulse width 10 ms. A second trigger arrives 3 ms after the first. What is the resulting output pulse width (in ms)?

Introduction / Context:
This problem checks understanding of pulse extension in a retriggerable one shot, such as the 74123 or a retriggerable 555 configuration. Retriggering during an active pulse restarts the timing interval.

Given Data / Assumptions:

• Nominal single trigger pulse width T = 10 ms.
• Second valid trigger occurs 3 ms after the first trigger edge.
• Inputs meet minimum width and level specs; no saturation or slew issues.

Concept / Approach:
In a retriggerable one shot, a new trigger during the active output restarts the internal timing, effectively extending the pulse. The final width equals time from first trigger until the last retrigger plus one full T after that retrigger.

Step-by-Step Solution:
1) First trigger starts a 10 ms pulse at t = 0.2) At t = 3 ms, a second trigger arrives while output is still high.3) The timing interval restarts at t = 3 ms, adding another 10 ms from that instant.4) Total pulse width = 3 ms + 10 ms = 13 ms.

Verification / Alternative check:
General rule: With multiple in window triggers, output duration equals time from first trigger to last trigger plus T. Here there are two triggers, last at 3 ms, so 3 + 10 = 13 ms.

Why Other Options Are Wrong:

• 3: Only the delay to retrigger, not the pulse width.
• 7: Misinterprets as remaining time of the original interval.
• 10: Ignores retriggering extension.

Common Pitfalls:
Confusing retriggerable with nonretriggerable; assuming the second trigger only adds the unused remainder.

Final Answer:
13