Tektronix 1502C User Manual page 78

1502C MTDR User Manual
Q8: What is resistance?
A8: Resistance is the opposition to DC current flow, or DC voltage divided by DC
current.
Q9: What is impedance?
A9: Impedance is the total opposition (resistance plus reactance) a circuit offers
to the flow of alternating current at a given frequency.
Q10: What factors determine the resistance of a cable?
A10: The cross sectional area (gauge), length, and the type of material the
conductor is made of (usually copper).
Q11: What factors determine the impedance of a cable?
A11: Dielectric value of the insulation and geometry of the conductors.
Q12: Why should cables of the same impedance be used?
A12: Because a mismatch of impedance means a loss of energy at the mismatch.
Q13: Why is that important to us?
A13: Because a TDR displays the energy reflected back from an impedance
mismatch.
Operator Tutorial
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