2-50
AMPLIFIER TYPE
COMMON
BASE
COMMON
EMITTER
COMMON
COLLECTOR
INPUT/OUTPUT PHASE
RELATIONSHIP
0º
180º
0º
VOLTAGE GAIN
HIGH
MEDIUM
LOW
CURRENT GAIN
LOW(!)
MEDIUM(")
HIGH(#)
POWER GAIN
LOW
HIGH
MEDIUM
INPUT RESISTANCE
LOW
MEDIUM
HIGH
OUTPUT RESISTANCE
HIGH
MEDIUM
LOW
TRANSISTOR CHARACTERISTICS are usually presented on specification sheets. These sheets
usually cover the following items:
1. The kind of transistor.
2. The absolute maximum ratings of the transistor.
3. The typical operating values of the transistor.
4. Additional engineering/design information.
TRANSISTORS ARE IDENTIFIED by a Joint Army-Navy (JAN) designation printed directly on
the case of the transistor. If in doubt about a transistor's markings, always replace a transistor with one
having identical markings, or consult an equipment or transistor manual to ensure that an identical
replacement or substitute is used.
2
N
130
A
NUMBER OF JUNCTIONS
(TRANSISTOR)
SEMI-
CONDUCTOR
IDENTIFICATION
NUMBER
FIRST
MODIFICATION
TESTING A TRANSISTOR to determine if it is good or bad can be done with an ohmmeter or
transistor tester or by the substitution method.
PRECAUTIONS should be taken when working with transistors since they are susceptible to
damage by electrical overloads, heat, humidity, and radiation.
TRANSISTOR LEAD IDENTIFICATION plays an important part in transistor maintenance
because before a transistor can be tested or replaced, its leads must be identified. Since there is NO
standard method of identifying transistor leads, check some typical lead identification schemes or a
transistor manual before attempting to replace a transistor.
