Chapter 3Chapter 3

Special Purpose DiodesSpecial Purpose Diodes

Fahmi SamsuriFahmi SamsuriAnalog Electronics Analog Electronics Faculty of Electrical & Electronic Faculty of Electrical & Electronic

Engineering, KUKTEMEngineering, KUKTEM

FIGURE 3-1 Zener diode symbol.

FIGURE 3-2 General diode V-I characteristic.

FIGURE 3-3 Reverse characteristic of a zener diode. VZ is usually specified at the zener test current, IZT, and is designated VZT.

FIGURE 3-4 Zener diode equivalent circuit models and the characteristic curve illustrating ZZ.

FIGURE 3-5

FIGURE 3-6

FIGURE 3-7 Partial data sheet for the 1N4728-1N4764 series 1 W zener diodes.

FIGURE 3-8 Zener regulation of a varying input voltage.

FIGURE 3-9

FIGURE 3-10

FIGURE 3-11 Equivalent of circuit in Figure 3-10.

FIGURE 3-12 Zener regulation with a variable load.

FIGURE 3-13

FIGURE 3-14

FIGURE 3-15

FIGURE 3-16 Basic zener limiting action with a sinusoidal input voltage.

FIGURE 3-17

FIGURE 3-18

FIGURE 3-19 The reverse-biased varactor diode acts as a variable capacitor.

FIGURE 3-20 Varactor diode capacitance varies with reverse voltage.

FIGURE 3-21 Varactor diode symbol.

FIGURE 3-22 Partial data sheet for the 1N5139-1N5148 varactor diodes.

FIGURE 3-23 A resonant band-pass filter using a varactor diode for adjusting the resonant frequency over a specified range.

FIGURE 3-24

FIGURE 3-25 Symbol for an LED. When forward-biased, it emits light.

FIGURE 3-26 Electroluminescence in a forward-biased LED.

FIGURE 3-27 Basic operation of an LED.

FIGURE 3-28 Examples of typical spectral output curves for LEDs.

FIGURE 3-29 General radiation pattern of a typical LED.

FIGURE 3-30 Typical LEDs.

FIGURE 3-31 Partial data sheet for an MLED81 1R light-emitting diode.

FIGURE 3-32 The 7-segment LED display.

FIGURE 3-33 Photodiode.

FIGURE 3-34 Typical photodiode characteristics.

FIGURE 3-35 Operation of a photodiode.

FIGURE 3-36 Partial data sheet for the MRD821 photodiode.

FIGURE 3-37 Symbol for a current regulator diode.

FIGURE 3-38 Typical characteristic curve for a current regulator diode.

FIGURE 3-39 Schottky diode symbol.

FIGURE 3-40 Basic internal construction of a Schottky diode.

FIGURE 3-41 PIN diode.

FIGURE 3-42 PIN diode characteristics.

FIGURE 3-43 Tunnel diode symbols.

FIGURE 3-44 Tunnel diode characteristic curve.

FIGURE 3-45 Parallel resonant circuit.

FIGURE 3-46 Basic tunnel diode oscillator.

FIGURE 3-47 Basic laser diode construction and operation.

FIGURE 3-48 Zener-regulated power supply test.

FIGURE 3-49 Indications of an open zener.

FIGURE 3-50 Indication of excessive zener impedance.

FIGURE 3-51 Basic system concept and block diagram of the counting and control system.

FIGURE 3-52 Zener regulated power supply preliminary schematic.

FIGURE 3-53 Basic schematics of the IR emitter and IR detector circuits.

FIGURE 3-54 Power supply and IR emitter/detector printed circuit board. All black resistor bands indicate values to be determined.

FIGURE 3-55 Power supply and IR emitter/detector test bench.

FIGURE 3-56 Test results of three prototype circuit boards.

FIGURE 3-57 Diode symbols.

FIGURE 3-58

FIGURE 3-59

FIGURE 3-60

FIGURE 3-61 File circuits are identified with a CD logo and are in the Problems folder on your CD-ROM. Filenames correspond to figure numbers (e.g., F03-61).

FIGURE 3-62

FIGURE 3-63

FIGURE 3-64

FIGURE 3-66

FIGURE 3-67

FIGURE 3-68

FIGURE 3-69

FIGURE 3-70

FIGURE 3-71

FIGURE 3-72