Electronics Handbook/Components/Diodes

Diode
Diode is a SemiConductor Device made from joining One Positive type Semi Conductor with One Negative Type Semi Conductor.
 * - o--[N P]--o +

Diode is an Unijuction device that has two distinct polarities namely Anode which is Negative and Cathode which is Positive. Diode has a circuit symbol


 * Diode_symbol.svg

Break-over Voltage

 * Vd = 0.3v for Si and 0.6v for Ge

Operation

 * V < Vd . I = 0 . Diode does not conduct current
 * V = Vd . I = 1 mA . Current starts to flow
 * V > Vd . I = ev . Diode conducts current exponentially

Polarities & Biased Voltage
When Diode is connected with a voltage source in such that the polarities of the diode is in opposite with the polarities of the voltage source Diode is said to be Forward Biased and when voltage is greter than Forward biased voltage current will flow and increase exponentially with time in the direction of Pointing Arrow

When Diode is connected with a voltage source in such that the polarities of the diode is in the same with the polarities of the voltage source Diode is said to be Backward Biased Diode does not conduct current

Diode's Types

 * {| class="wikitable" width=100%

! Component !! Diode
 * PN Diode || [[Image:Diode symbol.svg|100px|Diode symbol]]
 * Light Emitted Diode || [[Image:LED symbol.svg|100px]]
 * Schottky Diode || [[Image:Schottky diode symbol.svg|100px|Schottky diode symbol]]
 * Photo Diode || [[Image:Photodiode symbol.svg|100px]]
 * Varactor Diode || [[Image:Varicap symbol.svg|100px]]
 * Zener Diode || [[Image:Zener diode symbol.svg|100px|Zener diode symbol]]
 * Tunnel Diode ||[[Image:Tunnel diode symbol.svg|100px|Tunnel diode symbol]]
 * }
 * Varactor Diode || [[Image:Varicap symbol.svg|100px]]
 * Zener Diode || [[Image:Zener diode symbol.svg|100px|Zener diode symbol]]
 * Tunnel Diode ||[[Image:Tunnel diode symbol.svg|100px|Tunnel diode symbol]]
 * }
 * Tunnel Diode ||[[Image:Tunnel diode symbol.svg|100px|Tunnel diode symbol]]
 * }
 * }
 * }

Summary

 * {| class="wikitable" width=100%

! Component !! Diode Light Emitted Diode Schottky Diode Photo Diode Varactor Diode Zener Diode Tunnel Diode
 * Construction || Diode is made by joining one positive typed semi conductor with one negative typed semi conductor + o---[P N] ---o -
 * Symbol || [[Image:Diode symbol.svg]]
 * I - V Characteristics || [[Image:V-a_characteristic_diodes_si_ge.svg|200px]]
 * Break Over Voltage || Voltage where current is exactly 1mA . V_d = 0.3v Ge V_d = 0.6v Si
 * Conduction || Diode conducts when the polarities of diode is in reverse to the polarities of voltage source and forward biased voltage is greater than the break over voltage
 * Non Conduction || Diode does not conduct when the polarities of diode is in the same as the polarities of voltage source or forward biased voltage is less than the break over voltage
 * Current || I = 0  V < V_d   $$I = 1mA$$ ; $$V = V_d$$  $$I = I_s e^(\frac{V_d}{V})$$
 * Direction of Current flow || same as arrow direction
 * Diode Types || PN Diode [[Image:Diode symbol.svg|100px|Diode symbol]]
 * Conduction || Diode conducts when the polarities of diode is in reverse to the polarities of voltage source and forward biased voltage is greater than the break over voltage
 * Non Conduction || Diode does not conduct when the polarities of diode is in the same as the polarities of voltage source or forward biased voltage is less than the break over voltage
 * Current || I = 0  V < V_d   $$I = 1mA$$ ; $$V = V_d$$  $$I = I_s e^(\frac{V_d}{V})$$
 * Direction of Current flow || same as arrow direction
 * Diode Types || PN Diode [[Image:Diode symbol.svg|100px|Diode symbol]]
 * Direction of Current flow || same as arrow direction
 * Diode Types || PN Diode [[Image:Diode symbol.svg|100px|Diode symbol]]
 * Diode Types || PN Diode [[Image:Diode symbol.svg|100px|Diode symbol]]
 * Diode Types || PN Diode [[Image:Diode symbol.svg|100px|Diode symbol]]
 * }
 * }

Reference

 * Diode