Extech Instruments TK505 User manual

User's Guide
Autoranging True RMS Multimeter
Extech EX505

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Introduction
Congratulations on your purchase of the Extech EX505 True RMS Autoranging Multimeter.
This meter measures AC/DC Voltage, AC/DC Current, Resistance, Capacitance, Frequency,
Diode Test, and Continuity plus Thermocouple Temperature. It features a waterproof, rugged
design for heavy duty use This meter is shipped fully tested and calibrated and, with proper
use, will provide years of reliable service.
Safety
This symbol adjacent to another symbol, terminal or operating device
indicates that the operator must refer to an explanation in the Operating
Instructions to avoid personal injury or damage to the meter.
This WARNING symbol indicates a potentially hazardous situation, which
if not avoided, could result in death or serious injury.
This CAUTION symbol indicates a potentially hazardous situation, which
if not avoided, may result damage to the product.
This symbol advises the user that the terminal(s) so marked must not be
connected to a circuit point at which the voltage with respect to earth
ground exceeds (in this case) 1000 VAC or VDC.
This symbol adjacent to one or more terminals identifies them as being
associated with ranges that may, in normal use, be subjected to
particularly hazardous voltages. For maximum safety, the meter and its
test leads should not be handled when these terminals are energized.
This symbol indicates that a device is protected throughout by double
insulation or reinforced insulation.
PER IEC1010 OVERVOLTAGE INSTALLATION CATEGORY
OVERVOLTAGE CATEGORY I
Equipment of OVERVOLTAGE CATEGORY I is equipment for connection to circuits in
which measures are taken to limit the transient overvoltages to an appropriate low level.
Note – Examples include protected electronic circuits.
OVERVOLTAGE CATEGORY II
Equipment of OVERVOLTAGE CATEGORY II is energy-consuming equipment to be
supplied from the fixed installation.
Note – Examples include household, office, and laboratory appliances.
OVERVOLTAGE CATEGORY III
Equipment of OVERVOLTAGE CATEGORY III is equipment in fixed installations.
Note – Examples include switches in the fixed installation and some equipment for industrial
use with permanent connection to the fixed installation.
OVERVOLTAGE CATEGORY IV
Equipment of OVERVOLTAGE CATEGORY IV is for use at the origin of the installation.
Note – Examples include electricity meters and primary over-current protection equipment
WARNING
CAUTION
MAX
1000V

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SAFETY INSTRUCTIONS
This meter has been designed for safe use, but must be operated with caution. The rules
listed below must be carefully followed for safe operation.
1. NEVER apply voltage or current to the meter that exceeds the specified maximum:
Input Protection Limits
Function Maximum Input
V DC or V AC 1000VDC/AC rms
mA AC/DC 400mA AC/DC
A AC/DC 10A AC/DC (20A for 30 sec)
Frequency, Resistance, Capacitance,
Diode Test, Continuity, Temperature 600VDC/AC rms
2. USE EXTREME CAUTION when working with high voltages.
3. DO NOT measure voltage if the voltage on the "COM" input jack exceeds 600V above
earth ground.
4. NEVER connect the meter leads across a voltage source while the function switch is in
the current, resistance, or diode mode. Doing so can damage the meter.
5. ALWAYS discharge filter capacitors in power supplies and disconnect the power when
making resistance or diode tests.
6. ALWAYS turn off the power and disconnect the test leads before opening the covers to
replace the fuse or batteries.
7. NEVER operate the meter unless the back cover and the battery and fuse covers are in
place and fastened securely.
8. If the equipment is used in a manner not specified by the manufacturer, the protection
provided by the equipment may be impaired.

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Controls and Jacks
1. 4,000 count LCD display
2. RANGE button
3. Hz and % button
4. Mode button
5. Function switch
6. mA, µA and 10A input jacks
7. COM input jack
8. Positive input jack
9. Backlight button
10. REL button
11. HOLD button
Note: Tilt stand and battery compartment are on rear of unit.
Symbols and Annunciators
•))) Continuity
Diode test
Battery status
n nano (10-9) (capacitance)
µ micro (10-6) (amps)
m milli (10-3) (volts, amps)
A Amps
k kilo (103) (ohms)
F Farads (capacitance)
M mega (106) (ohms)
Ω Ohms
Hz Hertz (frequency) V Volts
% Percent (duty ratio) REL Relative
AC Alternating current Auto Autoranging
DC Direct current HOLD Display hold
ºF Degrees Fahrenheit ºC Degrees Centigrade

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Operating Instructions
WARNING: Risk of electrocution. High-voltage circuits, both AC and DC, are very
dangerous and should be measured with great care.
1. ALWAYS turn the function switch to the OFF position when the meter is not in use.
2. If “OL” appears in the display during a measurement, the value exceeds the range you
have selected. Change to a higher range.
DC VOLTAGE MEASUREMENTS
CAUTION: Do not measure DC voltages if a motor on the circuit is being switched ON or
OFF. Large voltage surges may occur that can damage the meter.
1. Set the function switch to the Vposition.
2. Press the MODE button to select DC (if necessary).
3. Insert the black test lead banana plug into the negative COM jack.
Insert the red test lead banana plug into the positive Vjack.
4. Touch the black test probe tip to the negative side of the circuit.
Touch the red test probe tip to the positive side of the circuit.
5. Read the voltage in the display.
AC VOLTAGE (FREQUENCY, DUTY CYCLE) MEASUREMENTS
WARNING: Risk of Electrocution. The probe tips may not be long enough to contact the
live parts inside some 240V outlets for appliances because the contacts are recessed
deep in the outlets. As a result, the reading may show 0 volts when the outlet actually has
voltage on it. Make sure the probe tips are touching the metal contacts inside the outlet
before assuming that no voltage is present.
CAUTION: Do not measure AC voltages if a motor on the circuit is being switched ON or
OFF. Large voltage surges may occur that can damage the meter.
1. Set the function switch to the V position.
2. Press the MODE button to select AC (if necessary)
3. Insert the black test lead banana plug into the negative COM jack.
Insert red test lead banana plug into the positive Vjack.
4. Touch the black test probe tip to the neutral side of the circuit.
Touch the red test probe tip to the “hot” side of the circuit.
5. Read the voltage in the display.
6. Press the HZ/% button to indicate “Hz”.
7. Read the frequency in the display.
8. Press the Hz/% button again to indicate “%”.
9. Read the % of duty cycle in the display.

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DC CURRENT MEASUREMENTS
CAUTION: Do not make 20A current measurements for longer than 30 seconds.
Exceeding 30 seconds may cause damage to the meter and/or the test leads.
1. Insert the black test lead banana plug into the negative COM jack.
2. For current measurements up to 4000µA DC, set the function switch
to the µA position and insert the red test lead banana plug into the
µA/mA jack.
3. For current measurements up to 400mA DC, set the function switch
to the mA position and insert the red test lead banana plug into the
µA/mA jack.
4. For current measurements up to 10A DC, set the function switch to
the 10A position and insert the red test lead banana plug into the
10A jack.
5. Press the MODE button to indicate “DC” on the display.
6. Remove power from the circuit under test, then open up the circuit at
the point where you wish to measure current.
7. Touch the black test probe tip to the negative side of the circuit.
Touch the red test probe tip to the positive side of the circuit.
8. Apply power to the circuit.
9. Read the current in the display.
AC CURRENT (FREQUENCY, DUTY CYCLE) MEASUREMENTS
CAUTION: Do not make 20A current measurements for longer than 30 seconds.
Exceeding 30 seconds may cause damage to the meter and/or the test leads.
1. Insert the black test lead banana plug into the negative COM jack.
2. For current measurements up to 4000µA AC, set the function switch
to the µA position and insert the red test lead banana plug into the
µA/mA jack.
3. For current measurements up to 400mA AC, set the function switch
to the mA position and insert the red test lead banana plug into the
µA/mA jack.
4. For current measurements up to 10A AC, set the function switch to
the 10A position and insert the red test lead banana plug into the 10A
jack.
5. Press the MODE button to indicate “AC” on the display.
6. Remove power from the circuit under test, then open up the circuit at
the point where you wish to measure current.
7. Touch the black test probe tip to the neutral side of the circuit.
Touch the red test probe tip to the “hot” side of the circuit.
8. Apply power to the circuit.
9. Read the current in the display.
10.Press the Hz/% button to indicate “Hz”.
11.Read the frequency in the display.
12.Press the Hz/% button again to indicate “%”.
13.Read the % duty cycle in the display.
14.Press the Hz/% button to return to current measurement.

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RESISTANCE MEASUREMENTS
WARNING: To avoid electric shock, disconnect power to the unit under test and
discharge all capacitors before taking any resistance measurements. Remove the
batteries and unplug the line cords.
1. Set the function switch to the Ω CAP position.
2. Insert the black test lead banana plug into the negative COM jack.
Insert the red test lead banana plug into the positive Ωjack.
3. Press the MODE button to indicate “Ω" on the display.
4. Touch the test probe tips across the circuit or part under test. It is
best to disconnect one side of the part under test so the rest of the
circuit will not interfere with the resistance reading.
5. Read the resistance in the display.
CONTINUITY CHECK
WARNING: To avoid electric shock, never measure continuity on circuits or wires that
have voltage on them.
1. Set the function switch to the ΩCAP position.
2. Insert the black lead banana plug into the negative COM jack.
Insert the red test lead banana plug into the positive Ωjack.
3. Press the MODE button to indicate” "and “Ω”on the display
4. Touch the test probe tips to the circuit or wire you wish to check.
5. If the resistance is less than approximately 100Ω, the audible
signal will sound. If the circuit is open, the display will indicate
“OL”.
DIODE TEST
1. Set the function switch to the ΩCAP position.
2. Insert the black test lead banana plug into the negative COM jack
and the red test lead banana plug into the positive Vjack.
3. Press the MODE button to indicate and Von the display.
4. Touch the test probes to the diode under test. Forward voltage will
typically indicate 0.400 to 0.700V. Reverse voltage will indicate “OL”.
Shorted devices will indicate near 0V and an open device will
indicate “OL” in both polarities.

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TEMPERATURE MEASUREMENTS
1. Set the function switch to the ºF or ºC position.
2. Insert the Temperature Probe into the input jacks, making sure
to observe the correct polarity.
3. Touch the Temperature Probe head to the part whose
temperature you wish to measure. Keep the probe touching the
part under test until the reading stabilizes (about 30 seconds).
4. Read the temperature in the display.
Note: The temperature probe is fitted with a type K mini connector.
A mini connector to banana connector adaptor is supplied for
connection to the input banana jacks.
CAPACITANCE MEASUREMENTS
WARNING: To avoid electric shock, disconnect power to the unit under test and
discharge all capacitors before taking any capacitance measurements. Remove the
batteries and unplug the line cords.
1. Set the rotary function switch to the ΩCAP position.
2. Insert the black test lead banana plug into the negative COM jack.
Insert the red test lead banana plug into the positive Vjack.
3. Press the MODE button to indicate “nF” on the display.
4. Touch the test leads to the capacitor to be tested.
5. The test may take up to 3 minutes or more for large capacitors to
charge. Wait until the readings settle before ending the test.
6. Read the capacitance value in the display
FREQUENCY/DUTY CYCLE MEASUREMENTS (ELECTRONIC)
1. Set the rotary function switch to the “Hz %” position.
2. Press the Hz/% button to indicate “Hz” in the display.
3. Insert the black lead banana plug into the negative COM jack and the
red test lead banana plug into the positive Hz jack.
4. Touch the test probe tips to the circuit under test.
5. Read the frequency on the display.
6. Press the Hz/% button again to indicate “%” on the display.
7. Read the % of duty cycle on the display.

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FREQUENCY SENSITIVITY (ELECTRICAL)
The frequency sensitivity is range dependent when the function is selected from while in
the voltage or current measuring function. Below are typical sensitivities for the “electrical”
measurement modes.
Range
( DC/AC )
Sensitivity Frequency width
4V ≥1.5V rms 5Hz~10kHz
≥10V rms 5Hz~20kHz40V, 400V
≥20V rms 5Hz~200kHz
1000V/1000V ≥420V rms 50Hz~1kHz
400mA ≥45mA rms 5Hz~5kHz
10A ≥4A rms 5Hz~1kHz
AUTORANGING/MANUAL RANGE SELECTION
When the meter is first turned on, it automatically goes into Autoranging. This automatically
selects the best range for the measurements being made and is generally the best mode
for most measurements. For measurement situations requiring that a range be manually
selected, perform the following:
1. Press the RANGE key. The “Auto” display indicator will turn off.
2. Press the RANGE key to step through the available ranges. Observe the decimal point
and units displayed until the preferred range is located.
3. To exit the Manual Ranging mode and return to Autoranging, press and hold the RANGE
key for 2 seconds.
Note: Manual ranging does not apply for the Capacitance and Frequency functions.
RELATIVE MODE
The relative measurement feature allows you to make measurements relative to a stored
zero reference value. A reference voltage, current, etc. can be stored and measurements
made in comparison to that value. The displayed value is the difference between the
reference value and the measured value.
1. Perform the measurement as described in the operating instructions.
2. Press the REL button to store (zero) the reading in the display and the "REL" indicator
will appear on the display.
3. The display will now indicate the difference between the stored value and the measured
value.
4. Press the REL button to exit the relative mode.
Note: The Relative function does not operate in the Frequency function.
DISPLAY BACKLIGHT
Press the backlight button for >2 second to turn on. Press the button again to turn the
backlight off.
HOLD
The hold function freezes the reading in the display. Press the HOLD key momentarily to
activate or to exit the HOLD function.
AUTO POWER OFF
The auto off feature will turn the meter off after 30 minutes. To disable the auto power off
feature, hold down the MODE button and turn the meter on.
LOW BATTERY INDICATION
The icon will appear in the display when the battery voltage becomes low. Replace the
battery when this appears.

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Maintenance
WARNING: To avoid electric shock, disconnect the test leads from any source of voltage
before removing the back cover or the battery or fuse covers.
WARNING: To avoid electric shock, do not operate your meter until the battery and fuse
covers are in place and fastened securely.
This MultiMeter is designed to provide years of dependable service, if the following care
instructions are performed:
1. KEEP THE METER DRY. If it gets wet, wipe it off.
2. USE AND STORE THE METER IN NORMAL TEMPERATURES. Temperature
extremes can shorten the life of the electronic parts and distort or melt plastic parts.
3. HANDLE THE METER GENTLY AND CAREFULLY. Dropping it can damage the
electronic parts or the case.
4. KEEP THE METER CLEAN. Wipe the case occasionally with a damp cloth. DO NOT
use chemicals, cleaning solvents, or detergents.
5. USE ONLY FRESH BATTERIES OF THE RECOMMENDED SIZE AND TYPE. Remove
old or weak batteries so they do not leak and damage the unit.
6. IF THE METER IS TO BE STORED FOR A LONG PERIOD OF TIME, the batteries
should be removed to prevent damage to the unit.
BATTERY INSTALLATION
WARNING: To avoid electric shock, disconnect the test leads from any source of voltage
before removing the battery cover.
1. Turn power off and disconnect the test leads from the meter.
2. Open the rear battery cover by removing two screws (B) using a Phillips head
screwdriver.
3. Insert the battery into battery holder, observing the correct polarity.
4. Put the battery cover back in place. Secure with the screws.
WARNING: To avoid electric shock, do not operate the meter until the battery cover is in
place and fastened securely.
NOTE: If your meter does not work properly, check the fuses and batteries to make sure that
they are still good and that they are properly inserted.
AA
A
B
B
F1 F2