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Unformatted text preview: e-Current Current-Voltage Characteristics Current-Voltage THE IDEAL DIODE Positive voltage yields f inite current Negative voltage yields zero current REAL DIODE The Ideal Diode Equation The qV I = I 0 exp − 1 , kT where I 0 = diode current with reverse bias q = 1.602 × 10 −19 coulomb , the electronic ch arg e eV k = 8.62 × 10 −5 , Boltzmann' s cons tan t K Semiconductor diode - opened region Semiconductor
s s The p-side is the cathode, the n-side is the anode The dropped voltage, VD is measured from the cathode to the anode to Opened: VD ≥ VF: VD = VF s ID = circuit limited, in our model the VD cannot exceed VF circuit Semiconductor diode - cut-off region Semiconductor
s Cut-off: 0 < VD < VF: ID ≅ 0 mA mA Semiconductor diode - closed region Semiconductor
s Closed: VF < VD ≤ 0: 0:
– VD is determined by the circuit, ID = 0 mA mA s Typical values of VF: 0.5 ¸ 0.7 V Zener Effect Zener
s Zener break down: VD <= VZ: VD = VZ, ID is determined by the circuit. In case of standard diode the typical values of the break In down voltage VZ of the Zener effect -20 ... -100 V down Zener diode
– Utilization of the Zener effect – Typical break down values of VZ : -4.5 ... -15 V s s LED LED
s Light emitting diode, made from GaAs
– VF=1.6 V – IF >= 6 mA Resistor in an Integrated Circuit Resistor...
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This note was uploaded on 04/04/2010 for the course EE 3 taught by Professor Staff during the Winter '08 term at UCLA.
- Winter '08