PC/CP300 Electronics Laboratory II

Power MOSFET

Equipment

• IRF510 -- Fairchild, International Rectifier

Procedure

Great care should be taken to avoid static discharge into the chips used in this lab and should always be taken when using CMOS based chips.

Remember you can't measure the "on" resistance of the MOSFET with an ohmmeter. You'll have to determine it indirectly.

1. Experimentally determine the following:
   • V_gs (off) or V_gs(th) as appropriate,
     
   • V_gs when R_on = stated value for the "on" resistance (from above)
     You may not be able to get the effective resistance down to the stated value of R_on. In that case see what it is when V_gs=7.2V (i.e. the robot battery voltage)
     
2. For a range of V_gs values, measure the effect on R_on. Graph your results. Explain your results.
   
   Demonstrate the effect of V_gs on R_on.