Frequency Counter  (220-0305)   Power Sources           Faxback Doc. # 6776

CHOOSING A POWER SOURCE

You can power the meter from a standard AC outlet or from four AA
batteries (alkaline or rechargeable nickel-cadmium).

USING AC POWER

You can power the counter from a standard AC outlet using a 9V adapter
(such as Radio Shack Cat. No. 273-1455, not supplied).

Caution:  Use only an AC adapter that supplies 9 volts DC, delivers at
          least 300 milliamps, and has a center negative plug that
          properly fits the counter's DC 9V jack.  Using an adapter that
          does not meet these specifications could damage the counter or
          the adapter.

Connect the adapter's barrel plug to the counter's DC 9V jack (on the
counter's left side).  Then plug the adapter's other end into a standard
AC outlet.


USING BATTERY POWER

You can power the counter using four AA batteries.  For the longest
battery life, use alkaline batteries (Radio Shack Cat. No. 23-552).  You
can also use nickel-cadmium rechargeable batteries (Cat. No. 23-125).

Installing the Batteries

Follow these steps to install the Batteries.

1.  Loosen the screw on the counter's battery compartment cover.  Then
    remove the cover.

2.  Install the batteries as shown inside the compartment.

3.  Set the counter's battery type switch according to the type of
    batteries you installed.  Use a small, pointed tool, such as a small
    screwdriver, to set the switch.

    Set the switch to the appropriate position-ALKALINE for alkaline
    batteries or NI-CAD for rechargeable nickel-cadmium batteries.

Warning:  If you installed alkaline or other non-rechargeable batteries,
          do not connect the AC adapter to the counter with the switch in
          the NI-CAD position.  Doing so activates the counter's charging
          circuit.  Trying to charge non-rechargeable batteries can cause
          the batteries to leak or explode, possibly causing personal
          injury.

4.  Replace the battery compartment cover.

To ensure consistent operation, replace alkaline batteries about every 12
months.

RECHARGING NICKEL-CADMIUM BATTERIES

To recharge nickel-cadmium batteries, connect the AC adapter to the
counter when the batteries are installed and set the battery-type switch
to NI-CAD.

LOW VOLTAGE INDICATION

When the battery voltage becomes too low, or there is a low AC voltage
condition, the counter might display incorrect measurements.  The display
shows a low-voltage condition by lighting the rightmost decimal point on
the display.

CONNECTING THE ANTENNA

The counter has a standard BNC-type connector.  To connect the supplied
antenna, place it over the counter's connector as shown.  Then slightly
push down on the antenna's connector and turn it clockwise until it locks.

Note:  You can also connect an antenna that is tuned to the frequency
       band of the signal you will measure (not supplied).

CONNECTING AN OPTIONAL COAXIAL CABLE

If you want to measure RF frequencies directly, connect a 50 ohms coaxial
cable or an osilloscope probe to the counter.  The cable must
end in a male BNC connector.

(LB/all-07/12/94)

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