The AC-50 indicates the approximate leakage current drawn by an AC appliance while it is turned OFF.  The unit uses the nonlinear effect of a diode placed in series with the HOT side of the AC line and the appliance.   The meter indicates relative current through the hot line and neutral and, by pressing the RED switch, through the hot line and earth ground.

Following are some readings that should be expected at various capacitance and resistance values.

    CAPACITANCE  (AT 60Hz)                                                 RESISTANCE

 VALUE (uFd)   METER  
  .001   .O4
  .005   .2
  .01   .38
  .05   .75
  .1   .83
    VALUE       METER     
  1 MEG   .1
  500K   .2
  100K   .65
  50K   .78
  10K   .95

Test the appliance with the power OFF.  The AC-50 is protected to loads up to 700 watts.

OPERATION:  Plug the appliance into the AC-50.   Plug the AC-50 into the power outlet.   If the line is HOT the RED lamp will light.  If the ground is good the YELLOW lamp will light.  The YELLOW lamp will NOT light is the HOT and NEUTRAL are reversed or if there is no ground.  Read the meter.   Press the RED button and read the meter.   If there is excessive current through either the neutral or ground paths further checking of the appliance is necessary.