I believe there may be some confusion in your statement. Sir John Ambrose Fleming, an English electrical engineer and physicist, is not credited with inventing the vacuum tube. The vacuum tube, also known as a thermionic valve, was actually invented by Thomas Edison and later improved upon by various scientists and inventors, including Fleming himself.

Sir John Ambrose Fleming is best known for his contribution to the development of electronics and electrical engineering. He made significant advancements in the field of electronics and telecommunications, particularly in the area of electric power transmission and wireless telegraphy. Fleming is credited with inventing the first practical electronic device known as the diode, which is a two-electrode device that allows current to flow in one direction only.

As for Fleming’s personality, he was described as a dedicated and hardworking individual with a keen intellect. He was known for his meticulous attention to detail and his passion for scientific research. Fleming had a reputation for being a serious and disciplined scientist who was deeply committed to his work. He had a strong sense of curiosity and a desire to explore and understand the fundamental principles of electricity and electronics.

Fleming was also a respected educator and author, having written several influential books on electrical engineering and physics. He held various academic positions, including the Chair of Electrical Technology at University College London.

Overall, Fleming was a highly accomplished and respected figure in the field of electrical engineering, known for his significant contributions to the development of electronics and his dedication to scientific research.」