Avtech AVR-3HG-B, Instructions Manual

Page: 23 / 38

OPERATIONAL CHECK
This section describes a sequence to confirm the basic operation of the instrument. It
should be performed after receiving the instrument. It is a useful learning exercise as
well.
Before proceeding with this procedure, finish read this instruction manual thoroughly.
Then read the “Local Control” section of the “Programming Manual for -B Instruments”
thoroughly. The “Local Control” section describes the front panel controls used in this
operational check - in particular, the MOVE, CHANGE, and ADJUST controls.
1. Connect a cable from the SYNC OUT connector to the TRIG input of an
oscilloscope. Connect a non-inductive 20W (or higher) 50Ω load to the OUT
connector and place the scope probe across this load. The load resistor must have
a voltage rating of at least 300V. The power dissipated in the resistor is given by
P = (V
2
/ R) × (PW / T) = (V
2
/ R) × PW × f
where “V” is the output voltage, “R” is the load resistance, “PW” is the pulse width,
and “T” is the pulse period (1/frequency), and “f” is the frequency.
2. Set the oscilloscope to trigger externally with the vertical setting at 100 Volts/div
and the horizontal setting at 1 us/div. Be sure that your oscilloscope and probe
setup can handle the maximum amplitude of 300V. A high-voltage attenuator might
be necessary to avoid damaging the probe and oscilloscope. The 50Ω load resistor
should be rated for at least 300V of voltage and 20W of power. Factory tests are
conducted using ten 2W resistors connected in a series-parallel combination to
make a 50Ω, 20W composite load. Ohmite “OY” ceramic composition resistors -
http://www.ohmite.com - are recommended for such applications. These resistors
23
AVTECH
PULSER
MAIN OUTPUT
CONNECTOR
SYNC
OUTPUT
AC
POWER
ALL CABLES: 50 OHM COAXIAL
REAL-TIME
OSCILLOSCOPE
CHANNEL A
TRIG
INPUT
SCOPE
PROBE
TEST
LOAD