Resistance meter circuit composed of milliammeter

Commonly used high-sensitivity meters actually use microamp meters. The resistance meter made with it can have a very low voltage, but the production method
and principle are still the same as those made with milliamp meters. The circuit is shown in Figure 5 37. When the total resistance
    of the current-following resistor and the internal resistance of the PA in Figure 5-37 is 24000fl, the current flowing in the circuit is 62.5vA, of which 50rA passes through the PA, and the remaining 12.5rA passes through the zero-ohm adjustment resistor. Horse and Rz. If you want this watch to be made into a resistance meter with a low or mid-range resistance value of 24fl center or 2400fl center , you can follow the dotted line in the figure. Install a 24fl or 24890 resistor .