Characteristics Hysteresis character ◦ It latches to its last position, on or off ◦ Example, physical s/w – you s/w it on, it remains on. May be viewed as 2 transistors working in pair. Constructed from bipolar junction technology.
Shockley Diode Not to be confused with schottky diode It is a four layer device Also known as PNPN diode.
The Working of the ShockleyDiode The four PNPN can be simplified to two set of separate transistors, PNP and NPN. P N P N P N
With high voltage, one of the transistor will be turnedon causing the other to be on. Once on, thetransistors latched. To turn off, the voltage must bereduced to cause the current to drop below minimum
DIAC Shockley diode works with DC. For AC, 2 shockleys are joint. The result is shown in the lower image
SCR Silicon Controlled Rectifiers or thyristors. Used to rectify AC and control the power output.
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