For a P-N junction diode, with increase in the reverse bias potential, the width of the depletion region ________ and the transition capacitance __________.

PN junction diode

Forward Bias: When the p-type side of the diode is connected to a higher potential than the n-type side, the diode is forward-biased. 

Reverse Bias: When the n-type side of the diode is connected to a higher potential than the p-type side, the diode is reverse-biased. 

Explanation

• Depletion Region: When a P-N junction is reverse-biased, the applied negative voltage on the P-side and positive voltage on the N-side push majority carriers away from the junction, widening the depletion region. This widening is because the reverse bias effectively increases the potential barrier, thus requiring more charge carriers to be depleted to maintain the barrier. 
• Transition Capacitance: The transition capacitance is a type of capacitance formed by the depletion region, acting like a dielectric between the P and N regions. As the depletion region widens with reverse bias, the capacitance decreases because the distance between the "plates" (P and N regions) increases, and the capacitance is inversely proportional to the distance. 

With increasing reverse bias potential in a P-N junction diode, the width of the depletion region increases, and the transition capacitance decreases.