6-
4
Effects of Frequency (F
s
) on the Diode Signature
Signatures of the same diode at different frequencies are shown below.
At F
S
= 2000Hz, the diode's signature has a slight circular loop added to it. This loop in the
signature is due to a physical characteristic of diodes called junction capacitance.
60 Hz 2000 Hz
V
S
= 3 V, R
S
= 100Ω
ΩΩ
Ω
Figure 6-5. Signature of a 1N914 Diode at Different Range Frequencies
Effects of Internal Resistance (R
s
) on the Diode Signature
Changing Tracker 2700's internal resistance R
S
moves the vertical knee portion of the diode's
Tracker signature. As R
S
increases, the knee of the signature moves inward toward the origin.
R
S
controls the current that's flowing through the diode so the forward diode voltage changes in
response to the current change.
R
s
= 100Ω
ΩΩ
Ω R
S
= 100 kΩ
ΩΩ
Ω
V
S
= 3 V, F
S
= 60 Hz
Figure 6-6. Signature of a 1N914 Diode at Different Range Resistances
Understanding Diode Signatures
To Next Page
Loading...
