9.1.4. Current Directions and Polarities

Try these first

1. 1.

   What is the necessary condition for the base-emitter junction of a p-n-p transistor?

   Hint

   Think about which terminal needs to be at a higher voltage.

2. 2.

   Which direction does the emitter current flow in a p-n-p transistor?

   Hint

   Remember the flow of current into the device.

3. 3.

   What must be true for the base-emitter junction of a p-n-p transistor?

   • It must be reverse biased
   • It must be forward biased
   • It can be either

   Hint

   Consider which voltage configuration allows current to flow.

4. 4.

   Is it true that the collector current exits the transistor in the same direction as the emitter current for a p-n-p transistor?

   • True
   • False

   Hint

   Visualize the flow of current directionally.

5. 5.

   Given a p-n-p transistor with V_EB = 0.7V and V_EC = -8V, calculate whether the transistor is in the active region and explain your reasoning.

   Hint

   Check the bias conditions of both junctions.

6. 6.

   Design a simple circuit using an n-p-n transistor, specifying required bias voltages to ensure proper functionality with given β value of 50.

   Hint

   Use Ohm’s Law and KCL to establish relationships.