Bipolar transistors

What is the collector dissipation of a transistor operating at a collector-emitter voltage of 5 V and a collector current of 100 mA?

  1. A50 W
  2. B0.05 W
  3. C0.5 W
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Answer: C. 0.5 W

The power turned into heat in a transistor (collector dissipation) is approximately PC = VCE × IC. 5 V × 0.1 A = 0.5 W. Designs must keep this below the maximum rating and ensure the heat can be removed.

  • A. 50 W results from mistaking the current for 100 A.
  • B. 0.05 W is an order of magnitude too small.
  • C. Correct. 5 V × 0.1 A = 0.5 W.
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More Bipolar transistors questions

  1. Which correctly describes the difference in how bipolar transistors and MOSFETs are controlled?
  2. In a common-emitter amplifier with transconductance gm = 40 mS and collector resistor RC = 5 kΩ, roughly what is the magnitude of the voltage gain? (Ignore the load.)
  3. What is the state of the junctions when a bipolar transistor is in the saturation region?
  4. When the output characteristics (IC-VCE) of a common-emitter transistor are plotted with base current IB as a parameter, what is characteristic of the active region?
  5. What does the load line drawn on the output characteristics of a transistor amplifier represent?