Radio Shack 22-168A, Owner'S Manual

Page 1: ... MANUAL DUAL DISPLAY OWNER S MANUAL DIGITAL MULTIMETER w PC Interface Please read before using this equipment Cat No 22 168A 8 zy y Sy a U1 Radio Shaek Ste ...

Page 2: ...on measures the capacitance of low voltage capacitors Dual Measurement Function shows both the AC voltage and frequency for AC measure ments or the logic level and ripple frequency for logic measurements Analog Bargraph Display indicates the mag nitude of the input compared to the full scale value of the measurement range MAX MIN Hold Function displays the maxi mum or minimum measured value on the...

Page 3: ...er Shut Off tums off after 10 min utes of non use to help conserve battery power Beeper sounds tones for overload warming continuity function and range selection Logic Test Function checks logic levels without extra logic probes Overload and Transient Protection helps protect the meter from accidental overload on most ranges Low Battery Indicator appears when you need to replace the batteries UL L...

Page 4: ... Stand Propping Up the Meter Hanging the Meter Pre Operation Check Making Measurements Understanding Phantom Readings Measuring High Voltage Circuits AC DC Voltage Measurement Measuring an AC Voltage on a DC Bias 5 Measuring 3 Phase AC Voltages Measuring AC DC Current Measuring Capacitance Measuring Resistance Checking Diodes Checking Continuity ...

Page 5: ... Using the Communication Feature Storing Measurements in Memory Recalling Stored Measurements Using the Comparison Measurement Feature Using the Dual Measurements Feature Using the Meter with a Computer Interfacing the Meter with a Compute Using the Supplied Software Technical Information Communication Parameters Data Format 0 00 Hints for Writing Your Own Software Replacing the Fuse 0 0ccse Care ...

Page 6: ... or 60 V DC Always dis connect power from the circuit you are mea suring before you connect the test probes to high voltage points e Never connect the test probes to a source of voltage when you select diode resistance continuity current measurement capacitance or hFE functions Always tum off the meter s power and disconnect the test probes before you replace the battery or fuse Never operate them...

Page 7: ...ESULT IN INJURY OR DEATH FOLLOW ALL SAFEGUARDS SUG GESTED IN THIS OWNER S MANUAL IN ADDI TION TO NORMAL SAFETY PRECAUTIONS IN DEALING WITH ELECTRICAL CIRCUITS DO NOT USE THIS DEVICE IF YOU ARE UNFA MILIAR WITH ELECTRICAL CIRCUITS AND TESTING PROCEDURES NOT FOR COMMERCIAL OR INDUSTRIAL USE ...

Page 8: ...isisinssantivartictns ta aieaebiskacinineniaiiacanitiinsiabicuinsndiinttiienstutcnteTOI65OF ROAGING ANd 1 2 of Full Scale 3 in Last Digit DC CURRENT vena Measurement ae 200 uA 2mA sada ssrnanssaniennsieunarunannannemennenenanae 1 0 of Reading and 0 5 of Full Scale 1 in Last Digit 1 5 of Reading and 1 2 of Full Scale 1 in Last Digit Q0A ores puna gunner setiineinnnnnnes 2 5 Of Reading and 2 0 of Fu...

Page 9: ...f Reading and 1 8 of Full Scale 5 in Last Digit 20A 3 5 of Reading and 3 0 of Full Scale 7 in Last Digit CAPACITANCE 200 pF 200 nF 2 5 of Reading and 2 0 of Full Scale 3 in Last Digit 20 uF 200 HF 4 5 of Reading and 4 0 of Full Scale 5 in Last Digit RESISTANCE 200 Ohm sue 1 Of Reading and 0 5 of Full Scale 3 in Last Digit ...

Page 10: ...ading and 5 0 of Full Scale 5 in Last Digit FREQUENCY QHZ ZO MZ ansscssssssseesensinennosesessseteon 2 5 of Reading and 2 0 of Full Scale 3 in Last Digit DIODE CHECK FUNCTION For checking semiconductors for open short or normal CONTINUITY TEST Continuity buzzer sounds at less than 40 ohms FE MEASUREMENT 00 cccesccssssseessns O 1000 HFE values for either PNP or NPN transistor Base DC Current about ...

Page 11: ...ELECTION inctnantoty 1 oe sss Manual rotary type switch POWER SOURCE ou sussussses 9 V battery such as Radio Shack Cat No 23 553 not supplied POWER CONSUMPTION cccccsssssssssssssssessesensesseeeeeenennee 70 mW typical LOW BATTERY INDICATION 00000 00 A battery symbol on the right of the display indicates when battery voltage drops below 6 5V 7 5V POLARITY sssceesssssessesseenseesetneeene Automatic ...

Page 12: ...F 0 to 40 C STORAGE TEMPERATURE swe 14 to 122 F 10 to 50 C WEIGHT 12 35 0z 350 grams SIZE vue TUX BUX 1 6 Inches 187 X87 X34 mm HWD ACCESSORIES included Fuse 2A 250V Fast Acting Type Shrouded Banana Type Probes RS 232C Cable 3 Inch Disk ...

Page 13: ... minutes in rest 200mA The maximum current that you can MAX measure at this terminal is 200 mA FUSED DC AC This terminal is limited to 2 amps by a fuse 500V MAX To avoid electrical shock or instru 4 ment damage do not connect the common input terminal COM to any source of more than 500 V with respect to earth ground MAX The maximum voltage this meter can 750V AC measure is 1000V DC or 750V 1000V D...

Page 14: ...Y Follow these steps to install the battery 1 Tum off power and disconnect the two test probes 2 Loosen the battery compartment cover screw and slide off the cover Remove the old battery if necessary Qe 3 Place the battery into the supplied insulation capsule and snap it onto the contacts S 4 Warning Do not discard the provided bat tery insulation capsule If you do not use this insulation capsule ...

Page 15: ...ur meter These test probes are rated for 1200 volts You can purchase replacement probes from your local Radio Shack store Cautions Although the test probes are rated for 1200 volts the maximum rating of your meter is 1000 volts DC and 750 volts AC If you try to measure DC voltages above 1000 volts or AC voltages above 750 volts you might damage your meter and expose yourself to a serious shock haz...

Page 16: ... meter on a benchtop the stand helps provide a better viewing angle To use the stand as a prop just open it away from the meter and set it on a flat surface 16 Hanging the Meter To hang the meter remove the stand by pressing the lower parts of the stand together Then insert the stand into the top two holes as ...

Page 17: ...he black probe into the meter s COM terminal and the red probe into the meter s V Q terminal 3 Rotate the function selector to 4 Your meter displays OL and the analog bargraph flashes 4 Touch the probe tips together Your meter sounds a tone 5 Rotate the function selector to one of the other OHM positions Your meter displays a value of less than 1 ohm when you touch the probe tips together ...

Page 18: ...eck a high voltage Circuit do not try to position both probes at once Instead clamp one probe to the neutral or ground lead of the circuit usually a bare green or white wire in AC wiring circuits using insulated Slip On Alligator Clips Cat No 270 354 Then probe for voltages with the other probe This helps pre vent you from accidentally touching a hot wire because you need to concentrate on only on...

Page 19: ...w these steps to measure AC DC voltage 1 Rotate the function selector to the desired po sition Select the range as required for the voltage level to be measured If you do not know the voltage level start with the range switch set to the highest voltage position and reduce the setting as needed to get a reading Press DC AC to toggle between DC and AC voltage AC appears for AC measurements Plug the ...

Page 20: ... Caution Never try to measure an AC voltage that is riding on a DC voltage level where the peak AC voltage exceeds 1000V with respect to earth ground MEASURING 3 PHASE AC VOLTAGES We designed this meter to measure household AC voltage It is not intended for commercial or industrial use If you want to measure 3 phase line to line voltages please note the following Waming Because of the dangers inhe...

Page 21: ...C CURRENT WARNINGS DO NOT APPLY VOLTAGE DIRECTLY ACROSS TERMINALS YOU MUST CON NECT THE METER IN SERIES WITH THE CIRCUIT THE 20A TERMINAL IS FUSED A SEVERE FIRE HAZARD AND SHORT CIRCUIT DAN GER EXISTS IF YOU APPLY A VOLTAGE WITH HIGH CURRENT CAPABILITY TO THIS TERMINAL THE METER CAN BE DE STROYED UNDER SUCH CONDITIONS To measure current break the circuit and con nect the probes to two circuit conn...

Page 22: ...black probe into your meter s COM terminal and the red probe into your meter s mA or 20A terminal 4 Remove power from the circuit under test and then bteak the circuit at the appropriate point 22 5 Connect the probes in series with the circuit 6 Apply power and read the current Your meter displays the current value Note If you set the meter for DC current appears or disappears This indicates the p...

Page 23: ... capa citance of a charged capacitor you might da mage your meter 2 Rotate the function selector to the desired CAP range LO for low value capacitors and HI for high value capacitors If you do not know the approximate capacitance value set the range to HI and reduce to LO to get a valid reading 3 Insert the discharged capacitor into the CAP connectors Your meter displays the capaci tance value Not...

Page 24: ...POWER REMOVED AND THAT ANY ASSOCIATED CAPACITORS ARE 2 Rotate the function selector to the desired FULLY DISCHARGED BEFORE YOU MAKE OHM range A RESISTANCE MEASUREMENT 3 Connect the probes to the device you want The resistance measuring circuit compares the to measure voltage gained through a known resistance internal with the voltage developed across the unknown resistance So when you check in cir...

Page 25: ...s internal resistance Make a note of this value and sub tract it from small resistance measurements for better accuracy For resistance of about 1 Megohm and above the display might take a few seconds to stabilize This is normal for high resistance readings CHECKING DIODES This function lets you check diodes and other semiconductors for opens and shorts Italso lets you determine the forward voltage...

Page 26: ...to 2 0 volts If the display indicates an overrange condi tion reverse the polarity of the connection If the display shows a value the device is good The displayed value is the component s actual forward voltage up to 2 0 volts If the display still indicates an overrange condition the device is open e If the display shows a value both before and after you reverse the polarity the device is shorted ...

Page 27: ...orrectly indi cates that the device is open CHECKING CONTINUITY Follow these steps to check a circuit s continuity 1 Rotate the function selector to 4 2 Plug the black probe into your meter s COM terminal and the red probe into your meter s V Q terminal 3 Remove power from the circuit Warning Never perform a continuity mea surement on a circuit that has power con nected 27 ...

Page 28: ...elector to the hFE posi tion Black Probe Red Probe 2 Insert the transistor you want to measure into the appropriate transistor socket Your meter displays the transistor s hFE value Resistor Note The buzzer sounds if the measured resis tance is below 40 ohms Notes Insert the base collector and emitter pins in the correct sockets as marked ...

Page 29: ...ipolar transistor Some power Darlington transistors contain an intemal base to emitter resistor Because the meter uses two current readings to calculate hFE any intemal transistor resistance causes undependable readings High voltage junctions in power transistors Prevent correct readings Also the larger leads of the power transistor can damage the test socket Do not try to determine hFE for power ...

Page 30: ...GE YOUR METER AND EXPOSE YOURSELF TO A SEVERE SHOCK HAZARD Follow these steps to measure the frequency of a signal 1 Rotate the function selector to FREQ Notes Input limit voltage AC 20V max Input sensitivity A 1Hz up to 1MHz 150 mV mms 2 Plug the black probe into your meter s COM 300 terminal and the red probe into your meter s Ate pr 18 20MZ Wms V Q terminal co ...

Page 31: ... It could damage the circuits to determine the logic state of different meter s intemal components or injure you parts of the circuit Rather than display an lute voltage this function displays HI LO or to indicate logic high logic low or undetermined respectively Follow these steps to perform a logic test 1 Rotate the function selector to the HIGH LOW logic range 31 ...

Page 32: ...en the black probe and the circuit s GND point move the red probe to the other desired points The meter immediately displays one of the three indications If the measured value exceeds 70 of the stored V value Hi HIGH appears If themeasured value falls below 30 of the stored V value Lo LOW appears If the measured value is between 30 and 70 of the stored V value appears Notes In this mode the Data H...

Page 33: ...lect one of the other advanced functions USING THE DATA HOLD FEATURE The data hold feature lets you hold a reading on the display To tum on thedata hold feature press FUNCTION until D H appears at the top of the display Both the main and secondary displays show the cur rent reading To hold a reading on the secondary display press SET RESET The main display continues to track the current measuremen...

Page 34: ...e ment and return to the auto hold function Or press FUNCTION to select another advanced fea ture Ky USING THE MAXIMUM FEATURE 1994 The maximum feature lets you measure the maximum value of a changing reading To tum on the maximum reading feature repeatedly press FUNCTION until MAX appears at the top of the display Both the main and secondary dis plays show the current reading Press SET RESET to a...

Page 35: ...s first digit Press SET RESET Note The first digit can be either 1 or nothing does not appear on the display for the first digit Repeat Step 3 for the other three digits After you enter the last digit the meter begins making rela tive measurements The main display shows the actual measurement The secondary display shows the difference between the measured value and the reference value USING THE CO...

Page 36: ...ary display shows the number of the memory you want to store a value in 4 While making a measurement press SET RESET to store the current measurement K3 RECALLING STORED MEASUREMENTS Follow these steps to recall a measured value from one of the ten memories 1 Repeatedly press FUNCTION until RCL appears at the top of the display 2 Repeatedly press UP or DOWN until the memory you want to recall appe...

Page 37: ...et the reference values and begin comparison measurements 1 Repeatly press FUNCTION until the meter displays CMP 2 Press UP or DOWN to set the minimum reference value s polarity appears for negative values Then press SET RESET 3 Press UP or DOWN to set the minimum feference value s first digit Then press SET RESET Repeat this step for the rest of the minimum reference valus s digits 4 Repeat step ...

Page 38: ...play Secondary Display AC Voltage AC Voltage Frequency Frequency Frequency AC Voltage Notes The meter indicates a frequency measure ment on the secondary display when you se lect the DC AC A resistance diode or hFE modes and tum on the dual function This measurement is not valid When you select dual measurement while measuring frequency the meter selects the 20V AC range for the secondary display ...

Page 39: ...eter The MS DOS program is called RS and is in the GRA PHIC subdirectory on the supplied diskette The Windows program is called Scopeview and is in the SCOPE directory on the supplied diskette Note You can not log frequencies on the com puter if the voltage exceeds 20V AC Using the DOS Software Follow these steps to install and run the MS DOS software Note The following steps assume a_ basic knowl...

Page 40: ...pecific opera ting instructions Notes If you donot have a hard disk you can still run the program from the supplied floppy dis kette Change to the GRAPHIC subdirectory on the diskette and type RS CENTER To stop the program or to escape from ade vice I O error press CTRL BREAK Using the Windows Software Follow these steps toinstall and run the Windows software Note The following steps assume a basi...

Page 41: ...PE VIEW icon Follow the on screen help for spe cific operating instructions Also refer to the README file in the diskettes SCOPE subdirectory for operation hints TECHNICAL INFORMATION You need the following information if you are writing your own interface software Communication parameters Transmission rate 1200 baud Character coding 7 bit ASCII Parity None Stop Bits 2 Data Format The data format ...

Page 42: ...computer must give the meter the D command to activate data transmission The following program is an example of a BASIC program that gets a single reading from the me ter 10 OPEN COM1 1200 N 7 2 RS CS DS CD AS 2 20 AS D PRINT 2 AS INS INPUTS 14 2 PRINT INS CLOSE 2 END s888s8 42 ...

Page 43: ...se of the specified voltage and current ratings F1 Radio Shack Cat No 270 1052 F 2 Radio Shack Cat No 270 1041 Follow these steps to replace the fuse 1 Tum off the meter and disconnect the test probes 2 Remove the cover by unscrewing the four screws and pulling off the meter s cover 3 Remove the blown fuse rov bs c oo oo Fl F2 4 Install the new fuse in the fuse compartment 5 Replace the cover and ...

Page 44: ... fully Dropping it can damage circuit boards and cases and can cause the meter to work improperly Keep your meter away from dust and dirt which can cause premature wear of parts Wipe your meter with a damp cloth occasionally to keep it looking new Do not use harsh chemicals cleaning solvents or strong detergents to clean the meter Use only a fresh battery of the recommended size and type Always re...

Page 45: ...rotection against radio and TV interference in a residential area However your meter might cause TV or radio interference even when it is operating pro perly To eliminate interference increase the dis tance between the meter and the radio or TV Consult your local Radio Shack store or an experienced radio TV technician if the problem still exists 45 ...

Page 46: ... cover a product subjected to misuse or accidental damage EXCEPT AS PROVIDED HEREIN RADIO SHACK MAKES NO EXPRESS WARRANTIES AND ANY IMPLIED WARRANTIES ARE LIMITED IN DURATION TO THE DURATION OF THE WRITTEN LIMITED WARRANTIES CONTAINED HEREIN Some states do not permit limitation or exclusion of implied warranties therefore the aforesaid limitation s or exclusion s may not apply to the purchaser Thi...