Tektronix 221 Instruction Manual page 52

DIAGRAMS
Symbols and Reference Designators
Electrical com ponents shown on the diagrams are in the fo llo w in g units unless noted otherwise:
Sym bols used on the diagrams are based on U SA Standard Y 32.2-1967.
Logic sym bology is based on M IL-S T D -806B in term s o f positive logic. Logic sym bols d e p ic t the logic fu n c tio n perform ed
and may d iffe r fro m the m anufacturer's data.
The fo llo w in g p re fix letters are used as reference designators to id e n tify com ponents or assemblies on the diagrams.
A
Assembly, separable or repairable
(circu it board, etc.)
A T A tte n u a to r, fixe d or variable
B M o to r
Battery
BT
C
Capacitor, fixe d or variable
CB C ircu it breaker
CR Diode, signal or rectifier
D L Delay line
DS Indicating device (lam p)
E
Spark Gap
F use
F
F L F ilte r
CIRCUIT BOARD ILLUSTRATIONS
AND
Capacitors = Values one o r greater are in picofarads (pF).
Values less than one are in m icrofarads (pF ).
Resistors = Ohms (fil).
H H eat dissipating device (heat sink.
heat radiator, etc.)
HR
Heater
H Y
H ybrid circuit
J C onnector, stationary p ortion
K
Relay
L Ind uctor, fixed or variable
LR 1 nductor/resistor com bination
M M eter
P C onnector, movable portion
Q
Transistor or silicon-controlled
rectifier
R Resistor, fixed or variable
Therm istor
R T
S
Switch
T T ransformer
TC
Therm ocouple
TP Test p oint
U Assembly, inseparable or non-repairable
(integrated circu it, etc.)
V
Electron tube
V R
Voltage regulator (zener diode, etc.)
Y Crystal
Z Phase shifter
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