Conductors•Insulators•

A material that has an electrical conductivity between a conductor and an insulator: http://en.wikipedia.org/wiki/Semiconductor

N-type - electrons as charge carriers

P-type - positively changed holes as charge carriers

Semiconductors•

Electrical Materials

Forward bias voltage (0.6 to 0.7 V - silicon)

Reverse bias voltage (breakdown voltage)

Diode equation

Diode Curve

Junction Diode (PN junction - Anode/Cathode)•

%Diode_curve.mq = 1.60E-19; % Charge of one electron -Columbk = 1.381E-23; % Boltzmann's constant J/KT = 273 + 27; % Temperature of the junction in Kelvin degreeI0 = 1E-9; % Reverse saturation current 1E-9 to 1E-15 Amp when reverse biasedVD = -1:0.1:1;ID = I0*((exp((q*VD)/k*T)) -1);plot(VD, ID,'*'), grid on

ON switch: P => + voltage, N => - voltage□

OFF switch: P => -, N => +□

Ideal Diode (switch)

Electronics switch□

Rectification (AC - DC conversion)□

Applications

Example 3.1: Half-Wave Rectifier Circuit

Class Discussion 3.2 - Inductive Kick: Flyback, Freewheeling, Snubber

xlabel('Volt'), ylabel('Amp'), title('Silicon diode curve')

Semiconductor-Based Electronics Devices

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1:17 PM

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Class Discussion 3.3 - Peak Detector

LED Circuit (Figure 3.13): 5V- 330Ω- LED (2V drop -9 mA)

LED (Light Emitting Diode)•

Photodiode Light Detector Circuit (Figure 3.14 - Reverse bias)

Photo Diode•

N-P-N transistor (Collector, Base, Emitter)

P-N-P transistor (Collector, Base, Emitter)

Forward Bias (P => +, N => -)□

Reverse Bias (P => -, N => +)□

Bias

IE = IC + IB

VCE = VC - VE

IC = β*IB

Common Emitter□

Common Collector□

Common Base□

Circuit Configurations

Figure 3.17 Common Emitter Circuit□

Figure 3.18 Common Emitter Characteristics□

Common Emitter Circuit

Transistor (Bipolar Junction Transistor)•

IC max = 200 mA

VCE (sat) = 0.2 V

hFE = β = 100

Vcc = 10V, Rc = 1k, Rb = 10k

Find Ic, Ib, Vin (min)

Example 3.4: Transistor Switch (Saturation)•

IB = (Vin - Vbe)/RB

Bipolar Transistor Switch (power transistor) - Figure 3.20•

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IB = (Vin - Vbe)/RB

Vcc = 5V

Rc = 100 ohms, LED

Rb = 10k ohms

Transistor 2N 2094

IB = (5 V - 0.7 V)/10k Ohm = 0.43 mA□

IC = (5 -2 -0.2)/100 = 0.028 =28 mA □

Calculation:

Example 3.2 LED Switch - Figure 3.2•

LAB3-Half-wave rectifier and full-wave rectifier

• Zener Diode

15 V regulator IC - LM 7815C

1.2 to 37 V adjustable regulator: LM317L

7805, 7812

Voltage Regulator: •

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