, only in one
direction) Therefore, such devices are generally referred to as valves These vacuum tube devices are bulky, consume high power, operate
generally at high voltages (~100 V) and have limited life and low reliability The seed of the development of modern solid-state semiconductor
electronics goes back to 1930’s when it was realised that some solid-
state semiconductors and their junctions offer the possibility of controlling
the number and the direction of flow of charge carriers through them