Heathkit IG-4505 - Page 33

Page 33
HEATH EIT?
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( ) Disconnect the BNC connector from the input of your
oscilloscope.
( ) Set the Calibrator TIME OUT switch to the 1 mS
position.
(_ ) Place the MULTIPLIER switch in the X1 position.
(_ ) Set your oscilloscope time base to 1 mS/cm.
( ) Connect oscilloscope test lead from the input of the
oscilloscope to the VOLTS OUT binding posts.
(_} Turn the VOLTS OUT switch through each of its
positions. You should obtain a waveform similar to
the waveform in Figure 1-2. The signal amplitude,
however, will reflect the setting of the VOLTS OUT
switch. Readjust the input attenuator of your
oscilloscope as necessary. WARNING: To avoid a
possible shock, do not touch the Volts Out signal
when the VOLTS OUT switch is in the 100V position.
(_ } Disconnect the oscilloscope leads from the Calibrator.
CALIBRATION
The Oscilloscope Calibrator can be calibrated with either a
DVM (digital voltmeter) or an analog voltmeter. The DVM
provides the greatest accuracy (usually greater than 1%).
Proceed to the method, either ‘‘Using a DVM" or “Using an
Analog Voltmeter,” that you are going to use.
Using a DVM
( ) Set the calibrator front panel switches as follows:
VOLTS OUT — 1V
TIME OUT — DC
MULTIPLIER — X1
( ) Slide the POWER switch to the ON position.
( ) Connect the DVM test leads to the VOLTS OUT
binding posts.
(_
)
Refer
to
Figure
1-3
in
the
Illustration
Booklet
and
adjust
the
CAL
control
R14
for
exactly
1.000
volts
DC
on
the
DVM.
( ) Disconnect the DVM test leads.
(_ ) Slide the POWER switch to the OFF position.
(_ ) Unplug the line cord from the AC outlet.
Proceed to ‘‘Final Assembly.”
Using an Analog Voltmeter
Set the Calibrator front panel switches as follows:
VOLTS OUT — 1V
TIME OUT — DC
MULTIPLIER — X1
( ) Slide the POWER switch to the ON position.
( ) Set the voltmeter to measure +5 volts DC.
( ) Connect the voltmeter ground lead to the black
VOLTS OUT binding post.
{ ) Measure the voltage at TP2 (on terminal strip AB lug
3). See Figure 1-3 in the Nlustration Booklet. Notice
and remember the exact meter indication.
(_ ) Measure the voltage at TP1 (on the foil side of the
circuit board). Adjust the CAL control R14 for the
same meter indication you obtained at TP2 in the
previous strip.
(_ ) Repeat the two previous steps several times to obtain
an accurate adjustment.
(_ ) Disconnect the test leads.
( ) Stide the POWER switch to the OFF position.
(_ )} Unplug the line cord ptug from the AC outlet.
Proceed to ‘’Final Assembly.”