Reference
Probe Selection
The probes included with your digitizing oscilloscope are useful for a wide
variety of tasks. However, for special measurement situations you sometimes
need different probes. This section helps you select the right probe for the
job.
Once you have decided the type of probe you need, use Table 3-7
(page 3-117) to determine the specific probe compatible with your TDS 600A
Digitizing Oscilloscope. Or use Table 3-8 (page 3-118) if you want to select
the probe by application.
There are five major types of probes: passive, active, current, optical, and
time-to-voltage probes. Most of these types are discussed here; see your
Tektronix Products Catalog for more information.
Passive voltage probes measure voltage. They employ passive circuit compo-
nents such as resistors, capacitors, and inductors. There are three common
classes of passive voltage probes:
General purpose (high input resistance)
Low impedance (Z
O
)
High voltage

General Purpose (High Input Resistance) Probes

High input resistance probes are considered “typical” oscilloscope probes.
The P6139A probes included with the digitizing oscilloscope are passive
probes. The high input resistance of passive probes (typically 10 M ) pro-
vides negligible DC loading and makes them a good choice for accurate DC
amplitude measurements.
However, their 8 pF to 12 pF (over 60 pF for 1X) capacitive loading can distort
timing and phase measurements. Use high input resistance passive probes
for measurements involving:
Device characterization (above 15 V, thermal drift applications)
Maximum amplitude sensitivity using 1X high impedance
Large voltage range (between 15 and 500 V)
Qualitative or go/no-go measurements

Passive Voltage

Probes