Which of the following is not transducer?

Options

A. Loudspeaker
B. Amplifier
C. Microphone
D. All of these

Explanation

To determine which of the following is not a transducer, we need to understand what a transducer is and analyze each option provided.

### Step-by-Step Solution:

1. **Define a Transducer**: A transducer is a device that converts one form of energy or signal into another. For example, it can convert sound waves into electrical signals or vice versa.

2. **Analyze the Options**:
- **Loudspeaker**: A loudspeaker converts electrical signals into sound waves. Therefore, it is a transducer.
- **Amplifier**: An amplifier increases the amplitude of electrical signals but does not convert them into another form of energy. Hence, it does not qualify as a transducer.
- **Microphone**: A microphone converts sound waves into electrical signals. Thus, it is also a transducer.

3. **Conclusion**: Since the amplifier does not convert signals from one form to another, it is not a transducer. Therefore, the correct answer is the amplifier.

### Final Answer:
The option that is not a transducer is **Amplifier**.

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