RDS (on) testing method for NMOS:

Step: 1. Connect the wires according to the diagram above,

              2. Set the V1 power supply to 10V, 
              3. The V2 power supply is set to within 5V and the current limit is set to 200mA,
              4. V1 is powered on, V2 is powered on, making the MOS tube conductive. Use a multimeter to measure the Vds voltage drop of the MOS tube 
              5. official calculation: RDS(on) (VGS=4.5V )= Vds / 200mA
              6. Measure RDS (on) (Vgs=4.5V) and set V1 to 4.5V.
              Note: 1. The multimeter probe should be placed as close as possibleMOS
                     2. Pay attention to unit conversion
                     3. During the testing process, if the MOS does not generate much heat, the current limiting can be set to 500mA or 1A to improve the testing accuracy