Avtech AVR-EB4-B, Инструкция по эксплуатации

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the reflections, placing them well after the transient where they may be ignored. A 5-
meter-long cable is supplied for this purpose.
For “soft-switching” diodes, the shortest possible cable length should be used. The
60-cm-long coaxial cable should be used for these applications. When a “soft switching”
diode nears the end of its reverse transient, the diode turns off more gradually. This
does not produce reflections, but the impedance mismatch that slowly develops means
that the attached cable acts as a capacitance. This tends to extend the waveform
slightly, leading to a small (~10%) over-estimation of the reverse recovery time.
In summary, the shortest possible coaxial cabling should be used, except when “hard
switching” causes noticeable reflections. In that case, use longer cable lengths.
Example waveforms are included in the “TYPICAL RESULTS” section.
ACCESSIBLE VOLTAGES
The mainframe provides pulsed voltages of up to 240V to the test jig. For this reason,
the output is automatically disabled when the test jig lid is open. The lid must be closed
to obtain measurements.
Shielded cabling should be used for all connections to the "IN" and "OUT"
terminals on the test jig, and the "OUT" connector on the mainframe.
When used properly (with R
C
= 50 Ohms), the maximum voltage on the OUT
terminal will be 24V, approximately. However, if R
C
is not connected, the maximum
voltage will at the OUT terminal may be as high as 240V. Avoid feeding this output
directly into an oscilloscope. Always use a probe, attenuator, or feed-through
terminator!
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