Page 21 - Electrician - TT (Volume 2)

ELECTRICIAN - CITS

F transistor for A.F. applications (not power types)
G multiple of dissimilar devices, miscellaneous devices
L power transistor for a.f. applications
N photo-coupler
P radiation sensitive device such as photo-diode, photo-transistor, photo-conducive cell, or radiation detector
diode
Q radiation generating device such as light-emitting diode
R controlling and switching devices (e.g. thyristor) having a specified breakdown characteristic (not power types)
S transistor for switching applications (not power types)
T controlling and switching power device (e.g. thyristor) having a specified breakdown characteristic.
U power transistor for switching applications
X multiplier diode such as varactor or step recovery diode

Y rectifier diode, booster diode, efficiency diode
Z voltage reference or voltage regulator diode, transient suppressor diode.
The remainder of the type number is a serial number indicating a particular design or development, and is in one
of the following two groups.

a Devices intended primarily for use in consumer applications (radio and television receivers, audio-amplifiers,
tape recorders, domestic appliances, etc.) The serial number consists of three figures.
b Devices intended mainly for applications other than (a) e.g. industrial, professional and transmitting equipments.

The serial number consists of one letter (Z,Y,X,W etc) followed by two numbers (digits)
The International System follows letters 1N, 2N, 3N etc followed by four numbers.
1N indicates single junction
2N indicates two junction

3N indicates three junctions.
The number indicates internationally agreed manufacturer’s code e.g. 1N 4007, 2N 3055, 3N 2000.
Again, manufacturers use their own codes for semiconductor devices. Manufacturers in Japan use 2SA, 2SB,
2SC, 2SD etc. followed by a group of numbers e.g. 2SC 1061, 2SA 934, 2SB 77. Indian manufacturers have
their own codes too.
Passive and active electronic components
Introduction: The Components used in electronic circuits can broadly grouped under two headings.

– passive components
– active components
Passive components: Components like resistors, capacitors, and inductors used in electronic circuit are called as
passive components. These components by themselves are not capable of amplifying or processing an electrical
signal. However these components are equally important in electronic circuit as that of active components,
without the aid of passive components, a transistor (active components) cannot be made to amplify electrical
signal.
Circuits formed with passive components obey the electrical circuits laws such as ohm’s law, Kirchoff’s Laws etc.,
Resistors: The components whose purpose to introduce resistance in the circuit is called as resistors. Other
details of resistors are dealt in earlier lessons.
Capacitor: The components whose purpose to introduce capacitance in the circuit is called as capacitor. The
unit of capacitance is ‘FARAD’. Commercially capacitors are available in Microfarad (mF), Nanofarad (nF) and
Picofarads (pF).

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CITS : Power - Electrician & Wireman - Lesson 60-69