GTC CT8022 Manual Download Page 2

4.3.1 DC Voltage measurement

• 

Set the 

FUNCTION

 

SWITCH

 to “

V

” and the 

RANGE SWITCH

 to 

DC/ 

” 

function.

• 

Connect the test leads across the source or load under 
measurement.

• 

The measurement and polarity will be shown the LCD Display 
when the probes are connected.

4.3.2 AC Voltage measurement

• 

Set the 

FUNCTION

 

SWITCH

 to “

V

” and the 

RANGE SWITCH

 to 

AC/ ” 

function.

• 

Connect the test leads across the source or load under 
measurement.

• 

The measurement will be shown on the LCD Display when the 
probes are connected and current 

fl

 ows through the meter.

4.3.3 DC Current measurement

• 

Set the 

FUNCTION

 

SWITCH

 to “

A

” and the 

RANGE SWITCH

 to 

DC/ 

” 

function.

• 

Connect the test leads in series with the source or circuit under 
measurement.

• 

The measurement and polarity will be shown the LCD Display 
when the probes are connected and current 

fl

 ows through the 

meter.

4.3.4 AC Current measurement

• 

Set the 

FUNCTION

 

SWITCH

 to “

A

” and the 

RANGE SWITCH

 to 

AC/ ” 

function.

• 

Connect the test leads in series with the source or load under 
measurement.

• 

The measurement will be shown on the LCD Display when the 
probes are connected and current 

fl

 ows through the meter.

4.3.5 Resistance measurement

  

CAUTION

:  Maximum Input Voltage for this function is 250 

Vrms for less than 10 Sec., do not exceed this 
rating to avoid personal injuries or damage to the 
instrument. Also ensure there is no  power applied  
to  the  component or circuit  and all capacitors are 
discharged.

• 

Set the 

FUNCTION

 

SWITCH

 to “

R

” and the 

RANGE SWITCH

 to 

DC/ 

” 

function.

• 

Connect the test leads across the component or circuit under 
measurement.

• 

The range will adjust automatically for optimal readout, and the 

measurement will be shown the LCD Display when the probe are 

connected.

4.4 Other Functions

  

CAUTION

:  Maximum Input Voltage for this function is 250 

Vrms for less than 10 Sec., do not exceed this 
rating to avoid personal injuries or damage to the 
instrument. Also ensure there is no  power applied  
to  the diode.

4.4.1 Continuity Test

• 

Set the 

FUNCTION

 

SWITCH

 to “

R

” and the 

RANGE SWITCH

 to 

AC/ ” 

function.

• 

Connect the test leads across the circuit or component to test.

• 

Buzzer will sound if the circuit resistance is below 100

.

4.4.2 Logic Level Test

• 

Set the 

FUNCTION

 

SWITCH

 to “

TTL

” and the 

RANGE SWITCH

 

to “

DC/ 

” 

function.

• 

Connect the test leads across the source or circuit under test.

• 

The logic level will be shown as “

HI

” or “

LO

” on the LCD display 

according to the table below:

© Copyright 2017 General Technologies

* The display will switch between HI and LO, but the response is 

affected by the pulses frequency

4.4.3 Display Hold

A push button switch at the back of the unit is used to hold display 

readings during measurements. 

• 

Pressing the button holds the display reading, and “

DH

” appears 

on the display. 

• 

Pressing the button again resumes normal operation.

4.4.4 Auto Power OFF

The meter will turn off automatically to extend the battery life after 

approx. 30 minutes without operating. To turn it on again, set 

the 

FUNCTION SWITCH

 to the “

OFF”

 position and then to the 

desired range position.

5. MAINTENANCE

  

CAUTION:

 

Before attempting battery removal  or replacement, 
disconnect test leads and remove the instrument 
from any energized circuit to avoid shock hazard.

5.1 Battery Replacement

• 

When the battery needs replacement, the battery symbol 

  will  

appear in the lower left hand side of the LCD display.

• 

To replace the battery, remove the screw at the back 

Battery 

Cover

 and replace with a new 9 V alkaline battery type NEDA 

1604 or IEC6F22, observing the polarity as indicated at the back 
of the case.

• 

Reinstall the battery cover and tighten the securing screw.

5.2 Fuse replacement

• 

To replace the internal fuse, turn the 

Fuse Cap

 counter clockwise, 

to release the Fuse Cap assembly. 

• 

Take out the blown fuse and replace with a type IEC60127-2 or 
UL248-14 (5 x 20mm) fast acting fuse, rated at 400mA/250V.

• 

Replace the fuse cap, by inserting it in the meter body and turning 
the 

Fuse Cap

 assembly clockwise, unitl it locks. 

5.3 Cleaning

Periodically wipe the case with a soft damp cloth and mild household 
cleanser. Do not use abrasives or solvents. Ensure that no water gets 
inside the instrument to prevent possible shorts and damage.

6. WARRANTY

One year  limited  warranty, excluding  batteries and fuses. For details  
see Standard Warranty Information in our webpage or you may request 
a printed copy.

Input Voltage

TTL Logic Status

Display

Above 2.0 V

High

HI

Below 0.8 V

Low

LO

0.8 to 2.0 V

Undertermined

-

Negative input (-V)

Undertermined

HI

/

LO

 or 

LO/HI

*

Pulse

Undertermined

HI

/

LO

 or 

LO

/

HI

*

General Technologies Corp.

#121 - 7350 72nd Street       Tel.: (604) 952-6699
Delta, BC V4G 1H9 

Fax: (604) 952-6690

Canada www.gtc.ca

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