1.2
Front-Panel Operation
1 – 5
1.1.7
Front and rear panels
Figure 1.2: The SIM918 front and rear panels.
1.2
Front-Panel Operation
1.2.1
Gain
The gain
R
F
of the preamplifier, in volts per microampere, is indicated
on the front panel of the instrument via a green annunciator LED.
2
Press one of the [GAIN
] buttons to change the gain. If [GAIN ]
is pressed when
R
F
=
1 V
/
µ
A, the press has no e
ff
ect. If [GAIN ] is
pressed when
R
F
=
100 V
/
µ
A, the press has no e
ff
ect.
A simultaneous press of [GAIN
] has a special meaning. This
press initiates autocalibration (Section 2.6).
1.2.2
Autozero
1.2.2.1
Engaging the autozero circuit
The autozero circuit is turned
ON
by the press of a front-panel button.
There will be a pause of up to 3.3 seconds (a wait for a positive-going
edge of the reference clock). At the end of the pause, the green
2
Note the minus sign in Eq. (1.1); the output voltage is positive for a current that
flows
out of
the input terminal.
SIM918
Precision Current Preamplifier
Summary of Contents for SIM918
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