7.2.1. Expression of Current Carried by Electrons

Try these first

1. 1.

   What is the role of electrons in a BJT?

   Hint

   Think about which particles are responsible for current flow.

2. 2.

   Define reverse bias in the context of BJTs.

   Hint

   Consider how voltage influences the flow of current.

3. 3.

   What happens to electrons under reverse bias in a BJT?

   • They are attracted to the collector
   • They are repelled towards the emitter
   • They stop moving

   Hint

   Consider the role of voltage in influencing current flow.

4. 4.

   True or False: BJTs can operate as amplifiers only when junctions are very far apart.

   Hint

   Reflect on the required conditions for transistor operation.

5. 5.

   Given a BJT with a collector area of 2 cm², a diffusion constant of 25 cm²/s, and minority carrier concentration of 1 x 10^16 per cm³, calculate the collector current when the length is 0.5 cm.

   Hint

   Make sure to convert units consistently.

6. 6.

   Explain and derive the expression for current carried by electrons in a simplified circuit using values provided for a hypothetical BJT, including the role of junction positioning.

   Hint

   Consider how each variable influences the others within the equation.