Making Current Measurements; Making Resistance Measurements; Making Continuity And Diode Checks; Making Frequency Measurements - TTI 1604 Manual De Instrucciones

Making Current Measurements

Having selected the appropriate current function (mA for 4mA and 400mA range, A for 10A
range), current measurements up to 400mA are made using the white mA socket and the black
COM socket; current measurements up to 10A are made using the 10A and COM socket. The
meter will show a minus sign (on dc measurements) when the polarity of the current is out of the
mA or 10A sockets.
Current measurements using the mA socket can be autoranged between the 4mA and 400mA
ranges; measurements up to 10A can be made using the 10A socket having selected the 10A
range with the A key.
The 4mA and 400mA ranges, using the mA socket, are protected by a 1A (F) HBC fuse and the
10A range, using the 10A socket, is protected by a 10A (F) HBC fuse. Both fuses are fitted inside
the instrument and replacement is described in the Maintenance section later in the manual.
Note: After measuring high current using the 10A input, thermal voltages are generated that may
create errors when making measurements on the most sensitive dc voltage, current or Ohms
ranges immediately afterwards. To ensure that the specified accuracy is maintained, allow 10
minutes for the thermal effects to fade before making sensitive measurements.

Making Resistance Measurements

Resistance measurements are made using the V/Ω and COM sockets.
Null can be used to null out residual test lead resistance, see Further Functions section.

Making Continuity and Diode Checks

Continuity and diode checks are made using the V/Ω and COM sockets.
Select Continuity mode by pressing SHIFT followed by Continuity; the continuity indicator is
shown in the display. The 4kΩ range is selected and readings below approximately 10Ω sound
the continuity buzzer.
Select Diode Test by pressing SHIFT followed by Diode Test; the diode annunciator is shown in
the display. The 4V range is selected and the diode voltage at approximately 1mA is shown
(3V maximum). Reverse diode connection will show overload (OFL).

Making Frequency Measurements

Frequency measurements are made using either the V/Ω and COM sockets (for AC voltages) or
mA/10A and COM (for AC currents).
First set the input sensitivity by selecting the appropriate AC volts or current range to give an in-
range measurement of at least 2,000 counts; then press the Hz key to select frequency mode.
Two ranges (4kHz and 40kHz) are available giving resolutions of .1Hz and 1Hz respectively over
an operating frequency range of 10Hz to 40kHz.
The default frequency range is 40kHz which has a 1s gate time. To select the 4kHz range (10s
gate time) use the arrowed down key; the Hz annunciator flashes slowly to indicate that the 4kHz
range has been selected. The 40kHz range can be reselected with the arrowed up key.
At low signal levels use a screened lead and an adaptor (BNC to 4mm plugs, 19mm pitch) to
preserve signal quality and avoid spurious readings from stray pick-up.
Note that the further functions of Null, Hold, T-Hold and Min-Max (next section) do not operate
with frequency measurement.
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