Difficulty: Easy
Correct Answer: +14 V dc
Explanation:
Introduction / Context:
The 78xx family are positive fixed-output linear regulators used in countless power supplies. The “xx” suffix indicates the nominal output voltage. Knowing these at a glance speeds up design and troubleshooting when scanning a board or a parts bin.
Given Data / Assumptions:
Concept / Approach:
For 78xx regulators, “xx” corresponds to the output voltage in volts. Examples: 7805 → +5 V, 7812 → +12 V, 7815 → +15 V. Therefore, 7814 provides a regulated +14 V DC output. The companion negative series are 79xx (e.g., 7912 for –12 V), not to be confused with 78xx.
Step-by-Step Solution:
Verification / Alternative check:
Datasheets from multiple vendors list VO = +14 V typical for 7814, with dropout and line/load regulation specs ensuring stable +14 V when input exceeds VO + dropout.
Why Other Options Are Wrong:
Common Pitfalls:
Final Answer:
+14 V dc
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