EXCEL DT9208A Digital Multimeter DC AC Voltage Current Resistance Capacitance Temperature Tester 

1. INIRODUCTION

This instrument is compact, rugged, battery operated, handheld 3 ¹/₂digit digital.

multimeter  for measuring DC and AC voltage, DC and AC current, Resistance and

Diode, Capacitance, Transistor, continuity Test and temperature or frequency

The Dual-slope A - D Converter uses C - MOS technology for auto - zeroing, polarity

Selection and over - range indication Full overload protection is provided. It is an

Ideal instrument for use in the field, laboratory, workshop, hobby and home

applications.

2.FEATURES

      Push-button ON-OFF power switch.

      Single 30 position easy to use rotary switch for FUNCTION and RANGE

Selection

      High sensitivity of 100µ V.

      Automatic overrange indication with the “1”displayed.

      Automatic polarity indication on DC ranges.

      All ranges fully protected.

      Resistance measurements 0.1Ω to 200MΩ.

      Capacitance measurements 1 pF to 20µ F.

      Diode testing with 1mA fixed current.

      Transistor hFE Test With ib -100µA.

      Temperature measurement with or without K type thermocouple.

3.SPECIFICATIONS

Accuracies are ± (%reading + No. of digits).

Gurranteed for 1 year, 23C±5C, less than 75%RH.

DC Voltage

Input Impedance: 10M ohm on all ranges.

Overload Protection: 1000V dc , or peak ac on all ranges.

AC Voltage

Input Impedance: 10M ohm on all.  ranges. .

Frequency Renge: 40Hz to 400Hz.

Overload Protection: 750V rms or 1000V peak continuous on ac ranges, except.

200mV ac range (15 seconds maximum above 300V rms)

Indication:  Average (rms of sine wave)

DC Current

Overload protection: 0.2/250V fuse.(20A range not fused)

Maximum.  lnput  Current: 20A, 15 sec.

AC CYRREBT

Overload Protection: 0.2A/250V fuse.(20A range not fused.)

Frequency Range: 40Hz to 400Hz.

Maximum Input Current: 20A 15 sec.

Indication: Average (rms of sine wave.)

Resistance

On 200M ohm range, if short the two test leads, display reading is 10

digits, this 10digits should be subtracted from measurement results.

Capacitance

Temperature

Using T type thermocouple probe

 Build - in temperature sensor.

Frequency Test

Overload Protection: A C 220 Vrms.

4. GENERAL CHARACTERISTICS

Maximum. Display                      : 1999 counts (3 ¹/₂digits)with automatic.

polarity indication and eng .unit.

Indication Method                      : LCD display.

Measuring Method                      : Dual -Slope integration A - D converter

system

Overrange Indication                   :”1”Figure only in the display.

Maximum common mode voltage       : 500V dc/ac rms.

Reading rate                            :2-3 reading per sec (approximate) .

Temperature for guaranteed accuracy   :23C to± 5C.

Temperature Ranges                    :Operating 0C to  40C,32° F to.

104° F Storage -10C to 50C,14° F to122° F.

Power Supply                           :One 9 - volt battery (NEDA 1604 6F22

TYPE or equivalent ).

Low Battery Indication :                         to left of display

Size                                     :88W × 170D  ×38H m/m  

Weight                                  :  340g (including 9 volt batteries)

Accessories                             :Operating manual. Set of test leads

Optional Accessories                    :Thermocouple (k type,400C)  .

Spare fuse (200mA/250V fast below type).

9V Battery (Zinc- Carbon type)(no battery)

Soft  Carring  case.

5. OPERATION

1. Check the 9 - volt battery by setting the ON - OFF switch to ON. If the battery is

weak,a  sign will appear on the display.

It this does not appear on the display, proceed as below. See MAINTENANCE if

the battery has to be replaced .

2. The mark, or sign,     next to the test lead jacks, is for warning that the in-

put voltage or current should not exceed the indicated values.

This is to prevent demage to the internal circuity.

3. The function switch should be set to the range which you want to test before operation

4. If the voltage or current range is not known beforehand set the FUNCTION

  switch to a high range and work down.

5. When only the figure “1”is displayed, over range is being indicatea and the

  FUNCTION switch must be set to a higher range .

5.1) DC Voltage Measurement

1.Connect the BLACK test lead to the COM jack and the .RED test lead to the V/Ωjack.

2. Set the FUNCTION switch to the V=range to be used and connect the test

  leads across the source or load under measurement.

  The polarity of the RED lead connection will be indicated at the same time as the voltage.

Note:

      Do not apply more than 1000v to the input .Indication is possible at

higher voltages but there is danger of damaging the internal circuitry

5.2) AC Voltage Measurement

1.Connect the BLACK test lead to the COM jack and the RED test lead to the V/Ωjack.

2. Set the FUNCTION switch to the V- range to be used and connect the test

leads across the source or load under measurement.

Note:

      Do not apply more than700 rms the input .Indication is possible at

higher voltages but there is danger of damaging the internal circuitry

5.3)DC Current Measurement

1.Connect the BLACK test lead to the COM jack and the RED test lead to the

  mA jack for a Maximum of 200mA.For a maximum of 20A,move the red test lead to

  the 20A jack .

2.Set the FUNCTION switch to the A - range to be used and connect the test leads in

series with the load under measurement .The polarity at the RED test lead connection

will be indicated at the same time as the current.

Note:

      The Maximum input current is 200mA ,or 20A depending on the jack used .

Excessive current will blow the fuse which must be replaced .The 20A range is not

protected by protected by a fuse .The fuse rating should be 200mA and no more to

prevent damage to the internal circuitry .The Maximum terminal voltage drop is 200mV.

5.4)AC Current Measurement

   1.Connect the BLACK test lead to the COM jack and the RED test lead to the

   mA jack for a maximum of 200mA.For a maximum of 20A,move the RED test lead to

 the 20A jack .

2.Set the FUNCTION switch to the A - range to be used and connect the test leads in

series with the load under measurement .

Note:

     The Maximum input current is 200mA ,or 20A depending upon the jack used .

Excessive current will blow the fuse which must be replaced .The 20A Range is not

protected by a fuse .The fuse rating should be 200mA and no more to prevent damage

to the internal circuitry .

The Maximum terminal voltage drop is 200mV.

5.5)Resistance Measurement

1.Connect the BLACK test lead to the COM jack and the RED test lead to the

V/Ωjack.(Note: The polarity of the RED test lead is “+”)

2.Set the FUNCTION switch to the Ω range to the be used and connect the test

leads across the resistance under measurement.

 Note:

1.      If the resistance value being measured exceeds the maximum value of the range

selected an over -range indication will be displayed (“1”) Select a higner range .For

resistance of approximately 1 megohm and above , the Meter may take a few

seconds to become stable. This is normal for high resistance readings.

2.      When the input is not connected, i. e. at open circuit ,the figure”1”will be displayed

for the over range condition.

3.      When checking in - circuit resistance, be sure circuit under test has all power

removed and that all capacitors are fully discharged.

 4.200MΩ range open circuit voltage is 3V.Display reading is 10 digits .when test

leads short ,this normal, when measure 10MΩ resistor (on 200MΩ range).display

is 20.measure 100Mohm (on 200M range)display reading is 110.The 10 digits is

a constant and should be subtracted from the reading.

5.6)Capacitance Measurements

1. Before connecting the test capacitor ,note the display which may have readings

   other than zero each time the range is changed .This offset  reading will not  at

   fect the accuracy for it can be overridden by true value.

2.Connect the test capacitor to the input sockets (not test leads) noting the polarity

  connections when required.

 Note:

1.When test individual capacitors insert the eads into the two sockets, with”+”(upper

socket)  ,”-” (Lower socket) ,at the left of the pannel .(Capacitors should be

 discharged before being inserted into the test -jack).

2.When testing polarized capacitors, for example, the tantalum type, particular

attention must be paid to the polarity connections, This is to prevent possible

damage to the capacitor

When testing large capacitances, note that there will be a certain time lag before the

final indication.

Units 1 pF =10^-6µF InF =10^-3µF

. Do not connect an external voltage or a charged capacitor (especially larger

capacitors) to the measuring terminals.

5.7)Diode Measurement and Continuity Test

1.Connect the BLACK test lead to the COM jack and the RED test lead to the V/Ωjack

(Note: The polarity of the RED test lead is “+”).

2.Set the FUNCTION switch to the     range and connect the test leads across the diode

 under measurement, display shows the approx forward voltage of this diode.

3.Connect the test leads to two points of circuit ,if the resistance is lower than approx 30Ω

  Buzzer sounds.

5.8) Transistor hFE Test

1.Set, the FUNCTION switch to the hFE range.

2.Datermine whether the transistor is NPN or PNP and locate the Emitter Base and collector

 leads into the proper holes in the socket on the front panel.

3.The display will read the approximate hFE value at the test condition Base Current 10µ A

 VCE 2.8V.

5.9) Temperature Measurement

1.Measure temperature with K type thermocouple, Set the FUNCTION switch to the T range

 and insert the K type thermocouple plug into KPROBE socket

2.Measure ambient temperature without probe .On the same T range. display reading

is the ambient temperature in C.

5.10)Frequency test  

1.Connect test Leads or shield cable to COM and F/V/Ωjack.

2.Set the FUNCTION switch to KHZ range ,and connect test leads or cable across the

 source or load under measurement .

Note:

1.                  Do not apply more than 220Vrms to the input ,indication is possible at voltage

voltage higher than 10Vrms ,but readings may be out of specification.

2.In noisy environment it is preferable to  use shield cable for measuring small signal.

5.11)Auto Power -off (Optional Function)

Automatic Power-off extends the life of the battery by turning the meter off if no

rotary function switch is operated for about 15 min .The meter turns back on if  either

the rotary switch is turned or the power switch is pressed again

6.MAINTENANCE

  Battery and /or fuse replacement should only be done aner the test leads have been

disconnected and POWER OFF

6.1)9-Volt Battery Replacement

Note the condition of the 9- volt battery using the procedure described above .if the

battery needs to be replaced, open the back cover remove the spent battery and replace it

with a battery of the same type.

6.2)Fuse Replacement

Should the fuse need replacement use only 200mA fuses identical in physical size to

 the original