Operation
2-19
Figure 2-13
Typical 2V analog output connections
INPUT
V,
Ω
GUARD
LO
HI
MEASURING DEVICE
(EXAMPLE: CHART RECORDER)
MODEL 6512
INPUT FROM
PREAMP
A. CONNECTIONS
S
2V ANALOG OUTPUT
COM
S
COM
RF = 2M
Ω
(X10)
200k
Ω
(X1)
20k
Ω
(X0.1)
2k
Ω
(X0.01)
10k
Ω
100
Ω
B. EQUIVALENT CIRCUIT
MODEL 6512
MODEL 1683
TEST LEAD KIT
INPUT RESISTANCE OF
MEASURING DEVICE
RL =
200k
Ω
2V ANALOG OUT
OFF
ON
7). Open-circuit voltage of 300V is present
at PREAMP OUT in the ohms function.
CAUTION
Connecting PREAMP OUT, COM, or 2V
ANALOG OUTPUT to earth while float-
ing input may damage the instrument.
Note that the PREAMP OUT output resistance is 100
Ω
. The
output resistance appears between Input Low and Analog
Output Low to keep the resistor out of the loop when using
external feedback elements. To keep loading errors under
0.1%, the device connected to the PREAMP OUT should
have a minimum input impedance of 100k
Ω
.
2.8.2 Preamp out
The PREAMP OUT of the Model 6512 follows the signal am-
plitude applied to the INPUT terminal. Some possible uses for
PREAMP OUT include buffering of the input signal, as well as
for guarding in the volts and ohms modes. Connections and
equivalent circuits for the preamp output are shown in Figure 2-
14. Full-range outputs for various functions and ranges are list-
ed in Table 2-7. Since the PREAMP OUT signal is not correct-
ed during calibration, gain errors of up to 3% may appear at this
output, depending on function and range selection. For all volts
ranges, PREAMP OUTPUT accuracy is typically 5ppm.
WARNING
High voltage may be present between the
PREAMP OUT and COM terminals de-
pending on the input signal (see Table 2-
Summary of Contents for 6512
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