Elenco Electronics LCM-1950 Operating Instructions Download Page 2

INDUCTANCE

Ranges: 4mH, 40mH, 400mH, 4H, 40H
Accuracy: +(5.0% rdg + 20 dgts) on 4mH

+(5.0% rdg + 10 dgts) on other ranges

Test Frequency: 200Hz

FREQUENCY  

(Autoranging)

Ranges: 4kHz, 40kHz, 400kHz, 1000kHz
Accuracy: +(0.5% rdg + 1 dgt) on all ranges
Sensitivity: 0.2V rms min.
Overload Protection: 500VDC or AC rms

LOGIC TEST

Threshold: Logic Hi (2.8 +0.8V)

Logic Lo (0.8 +0.5V)

Indication: 40 msec beep at logic low
Frequency Response: 20MHz
Detectable Pulse Width: 25nS.
Pulse Limits: >30% & <70% duty
Overload Protection: 500VDC or AC rms

TRANSISTOR h

FE

Ranges: 0 - 1000
Base Current: 10

m

ADC approx. (Vce = 3.3VDC)

OPERATION

Before taking any measurements, read the Safety Information
Section.  Always examine the instrument for damage,
contamination (excessive dirt, grease, etc.) and defects.
Examine the test leads for cracked or frayed insulation.  If any
abnormal conditions exist, do not attempt to make any
measurements.

Max. Hold Feature

Press “MAX” to toggle in and out of the Maximum Hold mode
(holding the highest reading).  In the MAX mode, the MAX
annunciator is displayed and maximum reading is stored in
display register.  If the new reading is higher than the reading
being displayed, the higher reading is transferred to the display
register.  A “higher” reading is defined as the reading with the
higher absolute value.

The MAX hold function is also available in the frequency count
mode.  The counter autoranging feature is disabled when the
MAX hold function is selected.

Voltage Measurements

1. Connect the red test lead to the “V

W

” jack and the black test

lead to the “COM” jack.

2. Set the Function/Range switch to the desired range and press

the “ /~” switch to toggle between the desired voltage type.
If the magnitude of the voltage is not known, set the switch
to the highest range and reduce until a satisfactory reading is
obtained.

3. Connect the test leads to the device or circuit being

measured.

4. For DC, a (–) sign is displayed for negative polarity; positive

polarity is implied.

Current Measurements

1. Set the Function/Range switch to the desired current range and

press the “  /~” selector switch to the desired current type.

2. For current measurements less than 400mA, connect the red

test lead to the “mA” jack and the black test lead to the
“COM” jack.

3. For current measurements over 400mA or greater, connect

the red test lead to the “10A” jack and the black test lead to
the “COM” jack.

4. Remove power from the circuit under test and open the

normal circuit path where the measurement is to be taken.
Connect the meter in series with the circuit.

Resistance and Continuity Measurements

1. Set the Function/Range switch to the desired resistance

range or continuity position.

2. Remove power from the equipment under test.

3. Connect the red test lead to the “V

W

” jack and the black test

lead to the “COM” jack.

4. Touch the probes to the test points.  In ohms, the value

indicated in the display is the measured value of resistance.
In continuity test, the beeper sounds continuously, if the
resistance is less than 100

W

.

Transistor Gain Measurements

1. Set the Function/Range switch to the desired h

FE

range (PNP

or NPN type transistor).

2. Never apply an external voltage to the h

FE

socket.  Damage

to the meter may result.

3. Plug the transistor directly into the h

FE

socket.  The sockets

are labeled E, B, and C for emitter, base and collector.

4. Read the transistor h

FE

(DC gain) directly from the display.

Capacitance & Inductance Measurements

1. Set the Function/Range switch to the desired Cx

(capacitance) or Lx (inductance) range.

2. Never apply an external voltage to the Cx/Lx sockets.

Damage to the meter may result.

3. Insert the capacitor or inductance leads directly into the

Cx/Lx sockets.

4. Read the capacitance or inductance directly from the display.

Frequency Measurements

1. Set the Function/Range switch to the KHz position.

2. Connect the red test lead to the “V

W

” jack and the black test

lead to the “COM” jack.

3. Connect the test leads to the point of measurement and read

the frequency from the display.

Logic Measurements

1. Set the Function/Range switch to the LOGIC position.

2. Connect the red test lead to the “V

W

” jack and the black test

lead to the “COM” jack.

3. Connect the red test lead to the test point and the black lead

to the common buss of the logic circuit.

4. A “     ” on the display indicates TTL logic high and a “     ”

indicates a TTL logic low.  Both indicators are on when the
point of measurement is toggling high and low.

Diode Tests

1. Connect the red test lead to the “V

W

” jack and the black test

lead to the “COM” jack.

2. Set the Function/Range switch to the “       ” position.

3. Turn off the power to the circuit under test.

4. Touch the probes to the diode.  A forward-voltage drop is

about 0.6V (typical for a silicon diode).

5. Reverse the probes.  If the diode is good, the display will be

between 2.800V and 3.200V.  If the diode is shorted, “.000”
of another number is displayed.

6. If the diode is open, the display will be between 2.800V and

3.200V in both directions.

7. If the junction is measured in a circuit and a low reading is

obtained with both lead connections, the junction may be
shunted by a resistance of less than 1k

W

.  In this case, the

diode must be disconnected from the circuit for accurate
testing.

MAINTENANCE

Battery Replacement

Power is supplied by a 9 volt “transistor” battery (NEDA 1604,
IEC 6F22).  The “     ” appears on the LCD display when
replacement is needed.  To replace the battery, remove the two
screws from the back of the meter and lift off the battery cover.
Remove the battery from the battery snap.

Fuse Replacement

If no current measurements are possible, check for a blown
overload protection fuse.  There are two fuses; F1 for the “mA”
jack and F2 for the “10A” jack.  For access to fuses, remove the
two screws from the back of the meter and lift off the battery
cover.  Replace F1 only with the original type 0.5A/250V, fast
acting fuse.  Replace F2 only with the original type 10A/600V,
fast acting ceramic fuse.

WARNING

Remove test leads before changing battery or

performing any servicing.

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