| S.N | Valve | S.N | Transistor |
| 1. | The charge carriers of valves are electrons. | 1. | The carriers of the transistors are the electron and holes. |
| 2. | In a valve the charge carries are provided by heater called hot cathode. | 2. | In a transistor, charge carriers are provided by emitter. No heater or heating elements are required. |
| 3. | It is not so efficient because large power is wasted in heating. | 3. | It is more efficient than valves since there is no wasting in heating. |
| 4 | A valve needs high power source of a few hundred volts. | 4. | It needs low power sources of a few volts. |
| 5. | A valve requires vacuum on its construction. | 5. | It does not require vacuum on its construction. |
| 6. | A valve does not work instantaneously since time is needed for heating. | 6. | It works instantaneously as the switch is on. |
| 7. | A valve has large size and more weight due to which it is not suitable to use in different electronic applications.
Image source: dreamstime |
7. | It has small size and light weight due to which it is more suitable to use in the modern electronic applications.
Image source: quora |
References:
i) https://onlinesciencenotes.com/differences-between-valve-and-transistor/#:~:text=Valve-,Transistor,potential%20difference%20has%20been%20applied.
ii) https://www.keith-snook.info/valves-versus-transistors.html
iii) https://sound-au.com/valves/valve-trans2.html