Operators  Familiarization
Probes
A probe provides the most convenient way to connect an input signal to the 
oscilloscope.  The standard  10X probes supplied with the 2245A are shielded 
against  electromagnetic  interference  and have  a high  input  impedance  for 
low circuit loading.  The subminiature probe bodies are designed for probing 
circuitry with  closely  spaced  leads.
SCALE  FACTOR  SWITCHING.  The  VOLTS/DIV  scale  factors,  displayed 
on  the  crt,  reflect  the  probe  attenuation  factor  when  Tektronix  coded 
probes  are used.
OPERATING  CONSIDERATIONS.  To  get  the  best  waveform  fidelity, 
keep probe  ground  and  signal leads  as  short  as  possible.
Misadjusted  probe  compensation  can  cause  measurement  error.  Check 
and  adjust  probe  compensation  whenever  a  probe  is  moved to  a  different 
channel  or  oscilloscope.  For  the  probe  compensation  adjustment  proce
dure,  see  Section 4  “Operator Checks And Adjustments” .
For detailed  operating  considerations  and  probe  maintenance,  see  the  in
struction  sheet  supplied with the  probe.
Coaxial  Cables
Signal  input  cables  can  greatly  affect  the  accuracy  of  a  displayed 
waveform.  To  maintain  original  frequency  characteristics  of the  input sig
nal,  use  only high-quality,  low-loss  coaxial  cables.  Coaxial cables  must  be 
terminated at both ends in their characteristic  impedance to prevent signal 
reflections within the cable.  Use  suitable impedance-matching  devices.
External  Trig gering
Any of the four vertical channels in the 2245A can be used as a source of A 
and  B trigger signals.  When you need a trigger signal source  different from 
the  one derived from  displayed signals,  you can use  any free vertical input 
channel.  CH  1  and CH 2 can  “condition”  a wide range of signals to produce 
triggers  over the full vertical deflection range from  millivolts to hundreds of 
volts.  CH 3 and CH 4 have two basic attenuation factors  (0.1  and 0.5 volts/ 
division),  making them  especially useful for triggering  on and viewing digital 
signal levels.
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2245A  Operators