When does the transistor act like an open switch?a.active regionb.cut off regionc.saturated regiond.inverted region

Break Down the Problem

1. Identify the function of a transistor in different regions of operation.
2. Determine which region corresponds to an open switch behavior.

Relevant Concepts

• A transistor operates in three primary regions: active, cut-off, and saturation.
  • Active Region: The transistor is conducting and can amplify signals.
  • Cut-off Region: The transistor is not conducting; it behaves like an open switch.
  • Saturation Region: The transistor is fully on and conducting maximum current.

Analysis and Detail

In the cut-off region, the transistor does not allow current to flow from collector to emitter, effectively making it act as an open switch. The base-emitter junction is reverse-biased, leading to no current flow through the device.

Verify and Summarize

Given the definitions of the regions:

• Cut-off Region corresponds to an open switch. Thus, the correct answer is the cut-off region, as it defines the state where the transistor prevents current flow.

Final Answer

b. cut off region