Definition: Shockley diode is a four layer (P-N-P-N) device. It conducts when it is forward biased and stops conducting when it is reverse biased. The major difference between conventional diode and Shockley diode is, it starts conducting when the forward voltage exceeds break-over voltage.

What is the working principle of Shockley diode?

In a Schottky diode, a semiconductor–metal junction is formed between a semiconductor and a metal, thus creating a Schottky barrier. The N-type semiconductor acts as the cathode and the metal side acts as the anode of the diode. This Schottky barrier results in both a low forward voltage drop and very fast switching.

How does a Shockley diode start conduction?

When the charging voltage of the capacitor reaches to the break over voltage of the diode, diode starts conducting and the capacitor starts discharging through the diode. This conduction of shockley diode drives the SCR into turn ON state, then the buzzer gives an alarm.