Multimeter DC current measurement circuit

Set the left switch of the multimeter to position A and the right switch to any current range position. A DC
current measurement circuit can be formed as shown in the figure .
    In the figure, the lkSl resistor and the adjustable resistor 1.4kfl are always connected in series with the meter
for temperature compensation. The rest of the resistors are connected as shunt resistors in a closed
circuit. When the range is 50yA, all the resistors are used as shunt resistors, including
the 121dl and 2.25kfl resistors. Inside. In other ranges, f connects
part of the shunt resistor in series to the meter branch, thereby reducing the actual shunt current.
Therefore, the current range can be changed by placing the switch in different range positions
.