SEMICONDUCTOR DIODE

SEMICONDUCTOR DIODE

1. A pn junction is known as a semi-conductor or crystal diode.

   • A crystal diode has two terminals. When it is connected in a circuit, one thing to decide is whether the diode is forward or reverse biased.
     • TERMINALS

2. that behaviour of diode is like a switch.

   • When the diode is forward biased, it behaves like a closed switch and connects the a.c. supply to the load RL.
   • when the diode is reverse biased, it behaves like an open switch and disconnects the a.c. supply from the load RL.

3. VOLTAJE-CURRENT CURVE

   • FORWARD RESISTANCE
     • DC
     • AC
   • REVERSE RESISTANCE
     • The resistance offered by the diode to the reverse bias is known as reverse resistance.

4. Equivalent Circuit

   • An equivalent circuit of a device is a combination of electric elements, which when connected in a circuit, acts exactly as does the device when connected in the same circuit.
     • Approximate Equivalent circuit
       • is a switch in series with a battery V0 and internal resistance rf
     • Simplified equivalent circuit
       • internal resistance rf of the crystal diode can be ignored in comparison to other elements in the equivalent circuit.
   • Ideal Diode Model
     • forward resistance rf = 0 and potential barrier V0 is considered negligible

5. Important Terms

   • Forward Current
     • It is the current flowing through a forward biased diode.
   • Reverse current
     • It is the current that flows through a reverse biased diode.
   • Peak Inverse Voltage
     • It is the maximum reverse voltage that a diode can withstand with- out destroying the junction.

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