
Model 187 & 189
Users Manual
Input Characteristics
Function
Volts, mV
Input Impedance (Nominal)
10 MΩ , < 100 pF
DC Volts, mV
AC Volts, mV
Common Mode Rejection Ratio
>100 dB at dc, 50 Hz or 60 Hz ±0.1%
> 90 dB dc to 60 Hz
Normal Mode Rejection
>90 dB at 50 Hz or 60 Hz ± 0.1%
Ohms
Diode Test
Open Circuit Test Voltage
<5 V
<5 V
| To 5 MΩ | 
 | 30 MΩ + nS | 
| 
 | 
 | 
 | 
| 500 mV | 
 | 3.1 V | 
| 
 | 
 | 
 | 
| 
 | 3.1000 V | |
| 
 | 
 | 
 | 
Typical 
Ohms
Diode Test
500Ω
1 mA
5 kΩ
100 ∝ A
| 
 | 50 kΩ | 
 | 500 kΩ | 
 | 
| 
 | 
 | 
 | ||
| 
 | 
 | 
 | 
 | 
 | 
| 
 | 10 ∝ A | 
 | 1 ∝ A | 
 | 
| 
 | 
 | 
 | 
 | 
 | 
| 
 | 1 mA | 
 | typical | 
 | 
5MΩ
0.1∝ A
30MΩ
0.1∝ A
