Question

exam lesson name: electricity and electronics
exam number: 700798rr
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question 8 of 20 :
select the best answer for the question.

1. a transmission system at a radio station uses a/an ______ to convert a direct current into a high - frequency alternating current.

○ a. demodulator
○ b. modulator
○ c. transmitting antenna
○ d. oscillator

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Explanation:

To solve this, we analyze each option:

• Option A: A demodulator extracts information from a modulated signal, not convert DC to high - freq AC.
• Option B: A modulator modifies a carrier wave with a signal, not convert DC to AC.
• Option C: A transmitting antenna radiates electromagnetic waves, not perform the DC - to - high - freq - AC conversion.
• Option D: An oscillator can generate alternating current, and in a radio station's transmission system, it can convert direct current into a high - frequency alternating current.

Answer:

D. oscillator