A15. Electron flow and hole flow.
A17. P-type crystal.
A19. To convert alternating current into direct current.
A20. Toward the arrow.
A23. N-type material.
A24. Depletion region.
A27. Any device that draws current.
A28. A pulsating dc voltage.
A29. Metallic rectifier.
A30. Forward bias.
A31. A characteristic curve.
A32. They are the limiting values of operating conditions outside which operations could cause diode
A33. A semiconductor.
A36. The diode is open or has a high-forward resistance.