Fluke 867B - Ma;Μa; Amps

867B,863
Service Manual
2-18
mA/µA 2-32.
Milliamp and microamp measurements are connected at the  and â inputs.
For the 300 mA and 30 mA ranges, input current flows through L9, F2, K1-4, K1-5, K1-
6, R42, and R109 to â. The voltage developed across R42 and R109 is sensed
through R151 by U16.
For 3000 µA and 300 µA ranges, input current flows through L9, F2, R49, R42, and
R109 to â. The voltage developed across R49, R42, and R109 is sensed through
R151 and R148 by U16.
For DC current (mA and µA), voltage is sensed through R82 to U30-9. U30 routes this
voltage to the active filter and the Slow A/D Converter.
For AC current (mA and µA), the voltage is sensed though another switch of U16 and
routed to the AC path.
Amps 2-33.
Amps measurements are connected at the á and â inputs. The current flows through
F1 and R109 to â. The voltage is sensed first though R42, then as described above
for mA/µA measurements.
Table 2-9. Amps Measurement Paths
Range Shunt Slow A/D Converter Range
300 µA R49, R42, R109 30 mV
3000 µA R49, R42, R109 300 mV
30 mA R42, R109 30 mV
300 mA R42, R109 300 mV
3A R109 30 mV
10A R109 300 mV