State three advantages and one disadvantage of a junction diode over a thermionic valve – NABTEB QUESTION

Advantages of a P-N junction over thermionic valve:

i. It is smaller in size
ii. It does not require a heater to operate to produce electrons
iii. It requires very low voltages to operate; therefore it can be operated with dry cell batteries of few volts.
iv. It requires no warm up time to produce electron, these are already inherently available.
v. Less likely to break

Disadvantages

(i) They conduct slightly in the reverse biased condition
(ii) They are temperature dependent.