12Installation3.2.4 Connect the AC adapterThe AC adapter (refer to Figure 3 on page 9, item 6) is used to charge the internal batteryand use the MET ONE 237 particle counter with a standard 115 VAC outlet.To connect the AC adapter:1. Turn off power to the MET ONE 237 particle counter.2. Attach the AC adapter to the power input jack (refer to Figure 6 on page 12) at theback of the MET ONE 237 particle counter.3.2.5 Install the RH/T probeTo install the RH/T probe:1. The RH/T probe is connected to the back of the unit (refer to Figure 6 on page 12,item 1).2. Attach the RH/T probe to the inlet so that the open end faces the direction of the airstream.Note: Make sure that the RH/T probe is attached before the counter is turned on.3.3 Rear panel connectionsThe power switch, fuse holders and all connectors are on the rear panel of the counter asshown in Figure 6 on page 12.Note: The connectors for Analog Out and Printer appear only in models with the Analog Outputoption, which do not have a built-in printer.Figure 6 Rear panel connections1 RH/T probe connector 3 Switch2 Optional connectors