Radio Shack 22-178 Owner's Manual

Cat. No. 22-178OWNER’S MANUALPlease read before using this equipment.Auto-Ranging LCDDigital Multimeter22-178.fm Page 1 Friday, August 6, 1999 11:3

10Resistance300 ohms–3–30–300 kohms ... ±1.0% of reading,±0.2% of full scale, ±1 in last digit3 M ohms ...

11Overrange Indication ...OL. (overload)appears on the display to indicate that the measurementexceeds the absolute maximum reading. Use car

12SPECIAL PANEL MARKINGS For your safety, we have added special markings to thepanel to remind you of the measurement limitations. 20 AThe maximum cur

13PREPARATIONINSTALLING BATTERIESYour meter requires two AA batteries for power. We rec-ommend alkaline batteries, such as RadioShack Cat. No.23-557.1

146. Replace the meter in the holster.When appears on the right side of the display, re-place the batteries.Warnings:• To avoid electrical shock, di

15Caution: Although these test leads are rated for 1200volts, the maximum rating of this meter is 1000 volts DC/750 volts RMS AC. Do not try to measur

16USING THE STAND AND HOLSTERThe fold-out stand lets you place the meter upright on aflat surface for easier viewing.The holster lets you hang the met

17USING THE METERBefore you use the meter the first time to make a mea-surement, follow these steps to confirm correct operationand to familiarize you

18Notes:• See the unit of measure on the display to distinguishthe range. For example, the meter displays mV in the300 mV range and V in the 300 V ran

19Connect the red lead to the V•W• •mA•mA• terminaland the black lead to the COM terminal. All connectionsexcept 20 A measurements are made at these t

2This symbol is intended to alert you to the presence of unin-sulated dangerous voltage within the product’s enclosurethat might be of sufficient magn

20MANUALLY SETTING THE RANGEWhen you measure voltages or resistance, your metercan automatically select a measuring range. When youmeasure current, th

21To cancel data hold, press DATA-H again or move the se-lector. USING THE BAR GRAPHThe meter also indicates all the measurements on thebar graph at t

22MAKING MEASUREMENTSMEASURING DC/AC VOLTAGECaution: The maximum input limit for voltage measure-ment is 1000V DC and 750V AC (RMS). If you try to mea

23Hint: When you use the meter to probe for a voltagein a high-voltage circuit, we recommend you do nottry to position both probes at once. Instead, u

24MEASURING AN AC VOLTAGE RIDING ON A DC SOURCE BIASTo measure an AC voltage superimposed on a DC volt-age source bias, you must first measure the DC

25Measuring Three-Phase AC VoltageWe designed this meter primarily to measure householdAC voltages. It is not intended for commercial or industri-al u

26MEASURING DC/AC CURRENTTo measure current, you must break the circuit and con-nect the leads to two circuit connection points. The con-nection must

273. Plug the black test lead into the COM jack and the redtest lead into the appropriate jack.4. Remove power from the circuit under test and dis-cha

28MEASURING RESISTANCEThe resistance-measuring circuit compares the voltagegained through a known resistance (internal) with thevoltage developed acro

29Caution: The meter has a circuit to protect the resistancerange from over-voltage (450 volts RMS AC, 1 minute).However, to prevent accidentally exce

3FEATURESYour RadioShack Auto-Ranging LCD Digital Multimeteris a portable 33/4-digit, compact multimeter that is idealfor field, lab, shop, bench, and

302. Press so appears on the display. Caution: NEVER CONNECT THE PROBES TO ASOURCE OF VOLTAGE while the selector is set to.3. Plug the red test lead

313. Plug the red test lead into the V•W• •mA•mA• jackand the black lead into the COM jack.4. Remove power from the circuit under test and dis-charge

32MAINTENANCEYour RadioShack Auto-Ranging LCD Digital Multimeteris an example of superior design and craftsmanship. Thefollowing suggestions will help

33Modifying or tampering with your meter’s internal compo-nents can cause a malfunction and might invalidate themeter’s warranty. If your meter is not

34Follow these steps to replace any blown fuse. 1. Turn off the power and disconnect the test leads.2. Remove the screw securing the back case and lif

35NOTES22-178.fm Page 35 Friday, August 6, 1999 11:38 AM

RadioShackA Division of Tandy CorporationFort Worth, Texas 761028A6 Printed in KoreaRadioShack Limited WarrantyThis product is warranted against defec

4Data Hold Function — holds the display so you can seethe reading even after you disconnect the probes.Overload and Transient Protection — helps prote

5CONTENTSA Word About Safety ... 6Specifications ...

6A WORD ABOUT SAFETYWe have taken every precaution in designing this meterto ensure that it is as safe as we can make it. But, safeoperation depends o

7• Because many AC/DC sets have a potentially hotchassis, be sure the top of your workbench and thefloor underneath it are made of non-conductive mate

8SPECIFICATIONSDisplay ... LCD 33/4-digits maximum,3200 count resolutionBar Graph ...

9DC Current300 mA/30 mA ......... ±1.0% of reading,±0.2% of full scale, ±1 in last digit3000 mA/300 mA ......