Question

Which of the following are three-terminal devices?

(A) Zener diode
(B) Photodiode
(C) Bipolar Junction Transistor
(D) Field Effect Transistor
Choose the correct answer from the options given below:

• A. (A), (B) and (D) only.
• B. (A), (B) and (C) only.
• C. (C) and (D) only.
• D. (B) and (D) only.

Hint:

BJTs and FETs are three-terminal devices; diodes (Zener and photodiode) are two-terminal devices.

Answer 1

The Correct Option is C

Step 1: Define three-terminal devices.
- A three-terminal device has three terminals: one for input, one for output, and one for control.
- Zener diode and photodiode are two-terminal devices.
- Bipolar Junction Transistor (BJT) and Field Effect Transistor (FET) are both three-terminal devices. The three terminals are the collector, base, and emitter for BJTs, and the source, gate, and drain for FETs.
Step 2: Conclusion.
Thus, the three-terminal devices are BJT (C) and FET (D).
Final Answer: \[ \boxed{\text{(C) and (D) only}} \]