Question

A piece of semiconductor is connected in series in an electric circuit. On increasing the temperature, the current in the circuit will ______.

• A. decrease.
• B. remain unchanged.
• C. increase.
• D. stop flowing.

Hint:

This property is why semiconductors undergo "thermal runaway" and physically melt if not cooled properly. Higher temp $\rightarrow$ lower resistance $\rightarrow$ higher current $\rightarrow$ more Joule heating ($I^2R$) $\rightarrow$ even higher temp!

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Semiconductors have a negative temperature coefficient of resistance. As temperature rises, their resistance decreases.

Step 2: Formula Application:
$R_T = R_0(1 + \alpha \Delta T)$. For semiconductors, $\alpha$ is negative.

Step 3: Explanation:
When the temperature increases, more covalent bonds break, releasing more charge carriers (electrons and holes). This lowers the resistance, which allows more current to flow according to Ohm's Law ($I = V/R$).

Step 4: Final Answer:
The current in the circuit will increase.