Electrical Engineering XYZ MCQs
What is the Potential barrier for Ge Diode:
- 0.3 V
- 0.03 V
- 0.7 V
- 0.5 V
Correct answer: 1. 0.3 V
Explanation: The potential barrier for a germanium (Ge) diode is typically around 0.3 volts. This barrier arises due to the formation of a depletion region at the junction between the p-type and n-type semiconductors in the diode.
When a p-type semiconductor (with positively charged holes as majority carriers) is joined with an n-type semiconductor (with negatively charged electrons as majority carriers), diffusion of charge carriers occurs. Electrons from the n-type material diffuse across the junction and combine with holes in the p-type material, forming a region depleted of charge carriers known as the depletion region.
This depletion region acts as a barrier to the flow of current in the reverse bias direction. The potential across this barrier is typically around 0.3 volts for a germanium diode. This means that if you apply a reverse bias voltage less than 0.3 volts across the diode, it will not conduct appreciable current. However, if you apply a forward bias voltage (positive to the p-type, negative to the n-type), the potential barrier is overcome, allowing current to flow through the diode.
So, the correct answer to the multiple-choice question would be:
Potential barrier for Ge Diode: 0.3 V