Radio Shack 22-178, Owner'S Manual

Page 1: ...Cat No 22 178 OWNER S MANUAL Please read before using this equipment Auto Ranging LCD Digital Multimeter 22 178 fm Page 1 Friday August 6 1999 11 38 AM...

Page 2: ...inform you that important operat ing and maintenance instructions are included in the litera ture accompanying this product RISK OF ELECTRIC SHOCK DO NOT OPEN CAUTION TO REDUCE THE RISK OF ELECTRIC SH...

Page 3: ...ve battery power by sounding a beep then turning off if you do not change any settings for 10 minutes Auto Ranging with Manual Ranging Override auto matically selects a range when you measure voltages...

Page 4: ...ck semi conductors for open shorted or normal junctions Auto Polarity Operation protects your meter and gives valid measurements even when you connect the leads in reverse polarity Low Battery Indicat...

Page 5: ...surements 18 Automatic Power Off 19 Manually Setting the Range 20 Holding a Measurement 20 Using the Bar Graph 21 Making Measurements 22 Measuring DC AC Voltage 22 Measuring an AC Voltage Riding on a...

Page 6: ...rking with voltages above 100V Always disconnect power from the cir cuit you are measuring before you connect test leads to high voltage points Never connect to a source of voltage when you select dio...

Page 7: ...self Take it to your nearest RadioShack store Service by unauthorized personnel voids the war ranty WARNING USE EXTREME CAUTION IN USE OF THIS DEVICE IMPROPER USE OF THIS DEVICE CAN RE SULT IN INJURY...

Page 8: ...of reading 0 2 of full scale 1 in last digit 30 300 V 1 0 of reading 0 2 of full scale 1 in last digit 1000 V 1 0 of reading 0 2 of full scale 1 in last digit Maximum Measurement 1000 Volts AC Volts 3...

Page 9: ...le 2 in last digit Maximum Measurement 20 A Measurement must be done within 30 seconds after 20 A input AC Current 300 3000 mA 30 300 mA 2 0 of reading 0 5 of full scale 1 in last digit Maximum Measur...

Page 10: ...nual range control for voltage and resistance measurements Semi auto and manual range for current measurements Polarity Automatic Minus sign for negative polarity Input Impedance 10 Megohm DCV ACV Mor...

Page 11: ...anges can dam age the meter and prevent an overrange indication Operating Temperature 32 to 122 F 0 to 50 C Storage Temperature 4 to 140 F 20 to 60 C Power Source Two AA batteries Power Consumption 5...

Page 12: ...electrical shock or instrument damage do not connect the common input terminal COM jack to any source of more than 1000 Volts with respect to earth ground Refer to complete operating instructions MAX...

Page 13: ...t leads 2 Remove the meter from the holster 3 Use a Phillips screwdriver to remove the screw that secures the back cover then lift off the cover 4 Install the batteries as indicated by the polarity sy...

Page 14: ...ce the batter ies and close the back cover Caution Never leave weak or dead batteries in the meter Even leak proof types can leak and damage the meter When you are not going to use the meter for a few...

Page 15: ...greater than 1000 volts DC 750 volts RMS AC USING ALLIGATOR CLIPS Alligator clips are supplied to allow you to keep your hands free while making measurements To attach the al ligator clips to the tes...

Page 16: ...place the meter upright on a flat surface for easier viewing The holster lets you hang the meter on a wall hold the test leads and protect the meter from damage if you drop it illus of meter w stand a...

Page 17: ...ements briefly appear 2 Set the selector to V 3 Press RANGE to set the meter to the manual range selection mode RH Range Hold appears on the dis play Press RANGE again The decimal point shifts each ti...

Page 18: ...ter is set to measure up to 1000 volts The display might show a phantom reading in some DC and AC voltage ranges when the test leads are not connected to a circuit This is normal The high input sensit...

Page 19: ...display when you measure resistance and do not have the leads connected to a component If you are measuring voltage or current im mediately disconnect the probes from the circuit AUTOMATIC POWER OFF Y...

Page 20: ...GE RH Range Hold appears on the display and the meter holds the range at its current setting Repeatedly press RANGE to change the measuring range To set the meter back to auto range control press and...

Page 21: ...nts on the bar graph at the bottom of the display The bar graph s length increases and decreases with the measured val ue You can easily observe changes in measurements by watching the bar graph Examp...

Page 22: ...Follow these steps to measure DC or AC voltage 1 Set the selector to V for DC voltages or V for AC voltages When you measure DC voltages appears on the display When you measure AC voltages appears on...

Page 23: ...for voltages with the other probe This helps prevent you from accidentally touching a hot wire since you need only concentrate on one test probe Warning Never clamp onto a hot wire usually red black...

Page 24: ...te the peak voltage us ing the formula AC voltage Peak voltage DC voltage 707 1 To measure the DC voltage set the selector to The display shows the DC voltage 2 To measure the AC voltage set the selec...

Page 25: ...do not use this meter for such applica tions The actual voltage can be greater than the cir cuit s rated line to ground voltage To determine the line to line voltage multiply the rated line to ground...

Page 26: ...in 30 seconds after 20 A input and allow the meter to cool for 15 minutes between such measurements 1 Set the selector to 320 3200 A 32 320 mA or 20 A Cautions If you do not know the amount of current...

Page 27: ...fore the value If you are using the 20A jack and setting and the measurement is less than 320 mA remove power from the circuit move the red test lead to the V W mA mA jack set the selector to 32 320 m...

Page 28: ...F VOLTAGE while the selector is set to W Note With no resistance connected across the test leads resistance infinite OL overload appears on the display when you set the selector to W This is normal 3...

Page 29: ...7 ohms This is due to the meter s and test lead s internal resistance You might need to take note of this value and subtract it from the measured value when you measure a very small resistance For re...

Page 30: ...ce is less than about 20 ohms the buzzer sounds indicating there is a short The display shows the actual circuit resistance CHECKING DIODES This measurement lets you check diodes transistors and other...

Page 31: ...ote the meter reading 6 Reverse the probes and note the second reading 7 Judge the semiconductor device as follows If one reading shows some value and the other is OL the device is good If both values...

Page 32: ...environments Temperature extremes can shorten the life of electronic devices and distort or melt plastic parts Handle the meter gently and carefully Dropping it can damage the circuit boards and case...

Page 33: ...BATTERIES OR FUSE THIS INSTRU MENT CONTAINS NO OTHER USER SERVICEABLE PARTS SERVICE SHOULD BE PERFORMED ONLY BY QUALIFIED PERSONNEL CAUTION For continued protection against fire replace the fuse on th...

Page 34: ...case and lift off the back cover 3 Remove the blown fuse 4 Replace the fuse with the spare fuse or a new fuse of the same rating 5 Replace the back cover and secure it with the screw WARNING DO NOT OP...

Page 35: ...35 NOTES 22 178 fm Page 35 Friday August 6 1999 11 38 AM...

Page 36: ...r ranty does not cover transportation costs Nor does it cover a product subjected to misuse or accidental damage EXCEPT AS PROVIDED HEREIN RadioShack MAKES NO EXPRESS WARRANTIES AND ANY IMPLIED WARRAN...