Vdc Scaling - Fluke 8842A Instruction Manual

8842A
Instruction Manual
5-5.

VDC Scaling

Scaling is performed in the VDC function by two precision resistors networks (Z301 and
Z302). These components are configured by relay K301, switching transistor Q311, and
quad analog switches U302A and U301B to provide the correct scaling for each range.
Voltage follower U306 provides high input impedance for the 20V dc range. A simplified
schematic and a switch state table for the VDC function are shown in Figure 5-2.
5-6
Figure 5-2. DC Scaling (VDC and mA DC)
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