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Question 5.16: What does the circuit of Fig. 5-25 do?

What does the circuit of Fig. 5-25 do?

5.25
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This is a blown-fuse indicator. If the fuse is OK, the LED is off because there is approximately zero voltage across the LED indicator. On the other hand, if the fuse is open, some of the line voltage appears across the LED indicator and the LED lights up.

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