Inputs; Output - Stanford Research Systems SIM910 Operating Manual

1 – 4

1.2.4 Inputs

overload limits

1.2.5 Output

Note about grounds
greater than 1 V, or the output is outside 10 V. The overload signal
can also be asserted on the status pin. See section 2.4.5.
The two input connectors, labeled A and B, are in the INPUT block
of the front panel. [Input] selects between A, A B, and Ground. A
& B are voltage inputs with input impedance of 100 M
with 35 pF. The connector shields are tied to each other, and can be
either floated or grounded to Signal Ground using [Shield]. Input
A is the non-inverting input. When input A B is selected, B is the
inverting input.
When input A is selected, the connector shield is used as the inverting
input, and acts as the reference for the A signal. Thus by selecting
Shield Float, a remote ground reference can be brought to the unit
using a single BNC. As long as the common-mode voltage limit is
satisfied, this configuration can be useful in breaking ground loops.
If the common-mode limits are exceeded, the inputs will be (sepa-
rately) clamped to
The maximum signal voltage is 1 V, while the maximum common
mode voltage is 5 V. Exceeding these limits will cause OVLD to
light up.
When the Ground input is selected, the user inputs A & B are left
floating and the amplifier is internally grounded at the front-end,
after the series resistors. The Input grounded noise is the limit of the
amplifier's noise.
Pressing [Couple] selects AC (16 mHz 3dB) or DC coupling.
The output of the instrument is located in the OUTPUT block of the
front panel. The output is referred to Signal Ground, which is tied to
the outside of the BNC connector.
The chassis of the SIM910 is tied to the power supply return, and not
Signal Ground. When operating in the SIM900, the chassis and Signal
Ground are tied together in the SIM900 Mainframe. If the amplifier is
operated with an independent supply, the output will be referenced
to Signal Ground (pin 1 on DB–15 J401). The Signal Ground and the
chassis are tied through back to back protection schottky diodes, so
they can't be more than
The instrument's output impedance is 50 , and can drive load
impedances from down to 50 . Note: when driving a 50
the gain will be half that displayed on the LEDs.
6 V through a series input resistor of 100 .
0 35 V apart.
SIM910 JFET Preamp
Operation
in parallel
load