Amprobe CR50A User manual

User Manual
• Bedienungshandbuch
• Manualdeuso
• Moded’emploi
CR50A
Capacitance,
Resistance Meter

Cx
200
n
20m
200p
200
ZERO
ADJUST
(20 )
OFF
20
2k
2M
20M
CR50
F
20
k
200
k
2m
200
20
2
20n
2n
CAP.
ZERO
ADJUST
Rx
DISCHARGE CAPACITOR
BEFORE CONNECTING
nF
pF
F
MF
Function/Range/
Off Selector
Funktion-/Bereich-
/Aus Schalter
Selector de
Función/Escala/Off
Sélecteur fon-
ctions/calibres/
marche-arrêt
Resistance
Zero
Adjustment
Nullabgleich
für Wider-
standsmessung
Ajuste de cero
para medidas
de resistencia
Mise à zero
pour mesure de
résistance
Capacitance Zero
Adjustment
Nullabgleich für
Kapazitätsmessung
Ajuste de cero para
medidas de
capacidad
Mise à zéro pour
mesure de
capacité
3-1/2 digit LCD; decimal point, function and unit indicators
3-1/2 Digit LCD ; Dezimalpunkt, Funktions- und Einheitsanzeigen
LCD de 3-1/2 dígitos, punto decimal, indicadores de función y unidades
LCD 3-1/2 digits ; point décimal, indicateurs de fonctions et d'unités
Input Terminals for resistance, diode
test and continuity
Eingänge für Widerstand, Durchgangs-
und Diodentest
Entradas para medidas de resistencia,
continuidad y prueba de diodos
Entrées pour mesure de résistance,
test de diodes et continuité
Capacitance Input Terminals
Eingänge für Kapazitätsmessung
Entradas para medidas de capacidad
Entrées pour mesure de capacité

CR50A
Capacitance,
Resistance Meter
User Manual
• Bedienungshandbuch
• Manual de uso
• Mode d’emploi
PN 1566212
©2007 Amprobe Test Tools.
All rights reserved. Printed in Taiwan

Limited Warranty and Limitation of Liability
Your Amprobe product will be free from defects in material
and workmanship for 1 year from the date of purchase.
This warranty does not cover fuses, disposable batteries
or damage from accident, neglect, misuse, alteration,
contamination, or abnormal conditions of operation or
handling. Resellers are not authorized to extend any other
warranty on Amprobe’s behalf. To obtain service during the
warranty period, return the product with proof of purchase
to an authorized Amprobe Test Tools Service Center or
to an Amprobe dealer or distributor. See Repair Section
for details. THIS WARRANTY IS YOUR ONLY REMEDY. ALL
OTHER WARRANTIES - WHETHER EXPRESS, IMPLIED OR
STAUTORY - INCLUDING IMPLIED WARRANTIES OF FITNESS
FOR A PARTICULAR PURPOSE OR MERCHANTABILITY,
ARE HEREBY DISCLAIMED. MANUFACTURER SHALL NOT
BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL OR
CONSEQUENTIAL DAMAGES OR LOSSES, ARISING FROM ANY
CAUSE OR THEORY. Since some states or countries do not
allow the exclusion or limitation of an implied warranty or
of incidental or consequential damages, this limitation of
liability may not apply to you.

1
Capacitance, Resistance Meter
Contents
Symbols.................................................................................... 1
Warnings and Precautions...................................................... 2
Overload Indication ................................................................ 2
Preparation For Use - Unpacking ........................................... 2
Measuring Procedures ............................................................ 2
Safety Test Leads ..................................................................... 4
Specifications........................................................................... 4
Troubleshooting/Maintenance ............................................... 6
Repair....................................................................................... 7
Symbols
Battery
Refer to the manual
Double insulated
Audible tone
Fuse
Complies with EU directives
Conforms to relevant Australian standards

2
WarningsandPrecautions
• Do not exceed the maximum overload limits per function (see
specifications) nor the limits marked on the instrument itself.
• Inspect instrument, test leads and accessories before every
use. Do not use any damaged part.
• Never ground yourself when taking measurements.
• Do not touch exposed circuit elements or probe tips.
• Never replace a fuse with one of a different rating. Do not
operate instrument in an explosive atmosphere.
OverloadIndication
Range overload is indicated by “1” in the display with
all other digits blanked. Select the next higher range
until a value is displayed. If overload condition still exists in the
highest range, the measured value is beyond the range of the
meter. Overload indication is normal in the OHMS range when
the leads are not connected to anything or when the measured
value is higher than the selected resistance range.
PreparationForUse-Unpacking
Your shipping carton should include the CR50A, one test lead set
(one black, one red), one pair of alligator clips, one 9V battery
(installed), one spare 0.1A/250V fuse (inside the case), a holster, a
warranty card and this manual. If any item is damaged or missing,
return to the place of purchase for an exchange.
MeasuringProcedures
General: When connecting or disconnecting test leads to/from
a circuit, always first turn off power to device or circuit being
tested and discharge all capacitors.
Resistance Measurement (Fig -1-)
1. Turn off power to the resistance to be measured
and discharge any capacitors. Any voltage present
during a resistance measurement will cause inaccurate
readings.·Connect red test lead to +Rx Input (red) and black
test lead to -Rx Input.
2. Set Function/Range Switch to the desired Ωposition.

3
3. Connect test leads to resistance or circuit to be measured.
4. Read resistance value on Digital Display. Open circuits will be
displayed as an overload condition.
Note: On the 20Ωrange, an adjustment potentiometer (ZERO
ADJ.) allows you to zero out the test lead resistance. Short the
test leads and adjust the knob until the display reads zero.
Diode and Transistor Test (Fig -2-)
The diode test measures the voltage drop across the diode junction.
1. Connect the red test lead to the +Rx Input (red) and the black
test lead to the –Rx Input.
2. Set the Function/range switch to position.
3. Apply probe tip of red lead to the anode and black lead to
the cathode of the diode. The meter’s display indicates the
forward voltage drop (approximately 0.7V for silicon diode
or 0.4V for germanium diode). Meter will display overload
condition for an open diode.
4. Reverse test lead connections to the diode to perform a
reverse bias test. Overload indicates a good diode.
Note: Overload condition for both reverse and forward bias tests
indicate an open diode. A low voltage reading for both bias tests
indicates a shorted diode. If the diode is shunted by a resistor of
1000 ohms or less, it must be removed from the circuit before
taking the measurement. Bipolar transistor junctions may be
tested in the same manner described above.
Continuity Test
The Continuity test checks electrical continuity between two
contact points.
1. Set the Function/Range switch to .
2. Plug the black test lead into the –Rx jack (black) and connect
the test lead tip to one of the contact points.
3. Plug the red test lead into the +Rx jack (red) and connect its
test lead point to the other contact point. (See Figure 1 for
connections).
4. The internal beeper emits a tone when resistance is less than
approx. 75Ω
Capacitance Measurement (Fig -3-)
Discharge all voltage from the capacitor (via a 100kΩresistor)
before measuring its value.

4
1. Connect the red test lead to the Cx+ input and the black test
lead to the Cx– input.
2. Set the function/range switch to the capacitance range that
gives the best resolution.
3. Apply probe tips to the capacitor leads. When measuring
electrolytic capacitors, observe correct polarity.
4. Read the capacitance value on the display (you may have
to wait a few seconds until the capacitor is fully charged). If
“OL” appears in the highest range, the capacitor is too large
to be measured.
Note: For small value measurements utilize CAP Zero Adjust to
eliminate test lead capacitance (±20pF).
Note: Small value capacitors can also be measured by inserting
their leads directly into the slots in the meter.
SafetyTestLeads
The test leads included with your meter have shrouded
banana plugs to eliminate the possibility of shock if the plugs
accidentally pull out of the meter while making a measurement.
Always inspect the test leads for damage before making any
measurements.
Specications
General Specifications
Display: 3 1/2 digit LCD, 1999 counts
Zero Adjustment: Adjustment potentiometer
Overrange Indication: “1” is displayed
Low Battery Indication: is displayed when the battery voltage
drops below accurate operating level. Change battery when
low battery is indicated.
Display Update Rate: 2/sec, nominal
Operating Temperature: 0°C to 50°C, 0 to 70% Relative Humidity
Storage Temperature: -20°C to 60°C, 0 to 80% RH, battery
removed
Power: Standard 9V transistor battery, NEDA 1604, JIS 006P, IEC
6F22
Battery Life (Typical): 200 hours alkaline, 150 hours carbon-zinc

5
Dimensions (H x W x D): 6.1 x 2.8 x 1.3 inches, (15.1 x 7.0 x 3.8 cm)
Weight (including battery): 8 ounces (200 grams)
Accessories: One pair of test leads, two alligator clips, one spare
fuse (FP125) installed in battery compartment, battery, holster
and Operator’s Manual
Agency Approvals: EMC
This product complies with requirements of the following
European Community Directives: 89/336/EEC (Electromagnetic
Compatibility) and 73/23/EEC (Low Voltage) as amended by
93/68/EEC (CE Marking).
However, electrical noise or intense electromagnetic fields in the
vicinity of the equipment may disturb the measurement circuit.
Measuring instruments will also respond to unwanted signals that may
be present within the measurement circuit. Users should exercise care
and take appropriate precautions to avoid misleading results when
making measurements in the presence of electronic interference.
Electrical Specifications
Accuracies at 23°C ± 5°C, <75% RH.
Resistance
Range Accuracy:
20Ω±1.2% rdg.
200Ω±(0.5% rdg +3 dgt)
2k-2MΩ±(0.5%rdg + 1dgt)
20MΩ±(3.0% rdg + 1dgt)
Resolution: 0.01 in 20Ωrg.
OL Protection, all Ranges: 500VDC or AC RMS
Open Circuit Voltage: 0.3VDC;
3.0VDC on 20Ωand 200Ωranges
Capacitance
Range Accuracy Test Frequency:
200pF ±(0.5% rdg +1 dgt +0.5pF) 820Hz
2000pF to 2µF ±(0.5% rdg +1 dgt) 820Hz
20µF ±(0.5% rdg +1 dgt) 82Hz
200µF ±(0.5% rdg +1 dgt) 8.2Hz
2mF ±(1% rdg +1 dgt) 8.2Hz
20mF ±(1.5% rdg +1 dgt) 8.2Hz

6
Test Voltage: < 3.5V
Input Protection: 0.1A/250V Fast Acting Fuse
Diode Test
Test Current/Voltage: 1mA (approx.) / 3.2VDC
Display: Forward Junction Voltage
Continuity Indicator
Audible Indication: Less than 75Ω
OL Protection: 500VDC or AC
Optional Accessories
VC30A: Vinyl Carrying Case (for meter and holster)
DL243D: Deluxe Test Lead Set
TL36A: Replacement Safety Test Leads w/alligator clips.
Troubleshooting/Maintenance
If there appears to be a malfunction during the operation of
the meter, the following steps should be performed in order to
isolate the cause of the problem:
1. Check the battery.
2. Review the operating instructions for possible mistakes
3. in operating procedure.
4. Inspect and test the Test Probes for a broken or intermittent
connection.
5. Inspect and test the fuse. See Fuse Replacement.
Except for the replacement of the battery or fuse, repair of the
multimeter should be performed only by a Factory Authorized
Service Center or by other qualified instrument service personnel.
The front panel and case can be cleaned with a mild solution
of detergent and water. Apply sparingly with a soft cloth and
allow to dry completely before using. Do not use aromatic
hydrocarbons or chlorinated solvents for cleaning.
Battery/Fuse Replacement
Warning
To prevent electrical shock hazard, turn off the
multimeter and any device or circuit under test and
disconnect the test leads before removing the rear
cover.