LCD Digital Multimeter (220-0166B) Operation Faxback Doc. # 15518 Before you use the meter the first time, follow these steps to confirm correct operation and to familiarize yourself with the meter's operation. 1. Set the function switch to kohm. 2. Turn on the power switch. After a slight delay, all the display elements appear for a second. Then, the display shows 10.00M ohm with a blinking 1. 3. Plug the red test lead into the left +diode/kohm/DCmA jack and the black lead into the -COM jack. 4. Touch the test lead's probe ends together. The meter's dial moves to the 200ohm range (ohm mark appears on the display) and shows only the small resistance of the test leads - no more than 0.5 ohms. Range and Display The meter automatically sets to the highest range that gives the best reading. Read the range in volts, ohms, or amps as indicated by the position of the decimal point. Functions Range Display DCV/ACV 200mv(DCV only) ddd.d mV 2V d.ddd V 20V dd.ddV 200V ddd.d V 2000V dddd V DCmA 200 mA ddd.d mA k ohm 200 ohm ddd.d 2 kohm d.ddd k 20 kohm dd.dd k 200 kohm ddd.d k 2000 kohm dddd k Diode Check 2V (Fixed) d.ddd Notes: In some DC and AC voltage ranges, with leads not connected to any circuit, the display might show a phantom reading. This is normal. The high input sensitivity produces a wandering effect. When you connect the test leads to a circuit, a real measurement appears. Use the unit of measure on the display to determine the range when two ranges have the decimal point in the same position. For example, on the 200 mV range, the meter display is mV versus V on the 200 V range. MAKING MEASUREMENTS DC/AC VOLTAGE MEASUREMENT CAUTION: The maximum input limit for voltage measurement is 1000V DC and 750V AC (RMS). Never try to measure a DC voltage above 1000 volts or an AC voltage above 750 volts RMS. Follow these steps to measure DC or AC voltage. 1. Set the function switch to DCV or ACV. 2. Plug the red lead into the right + DC 1000V, AC750V MAX jack and the black lead into the -COM jack. 3. Connect the probes to the circuit you want to test. When you measure DC voltages, the minus sign appears if you connect the black lead to a point in the circuit that has a higher voltage potential than the point where you connect the red lead. When you measure AC voltage, AC appears on the display. The range automatically moves to the range that gives the best reading. Notes: On 200V and 200 mV ranges, the decimal point appears in the same position (one place to the left). To distinguish between the two ranges, see the unit display - mV appears on the display in the 200 mV range. When you select the DCV or ACV function, the display might show small changes in the lower ranges before you connect the probes to a circuit under test. This is normal. A high input impedance produces this wandering effect. When you connect to a circuit, you get the normal accurate measurement. HINT: When you use the meter to probe for a voltage in a high-voltage circuit, we recommend you do not try to position both probes at once. Instead, clamp one lead to the neutral or ground lead of the circuit (usually a bare, green, or white lead in AC wiring circuits) using our insulated Slip-On Alligator Clips (Cat. No. 270-354). Then, probe for voltages with the other probe. This helps prevent you from accidentally touching a hot wire, because you need concentrate on only one test probe. WARNING: Never clamp on to a hot wire, (usually red, black, or blue in AC Wiring circuits). If you do so and then touch the other probe connected to the meter, you could receive an electric shock. AC VOLTAGE RIDING ON A DC SOURCE BIAS MEASUREMENT You can measure an AC voltage superimposed on a DC voltage source bias. Connect a 0.1 microfarad/100 V mylar capacitor in series with the positive terminal of the voltage source and the (+) test lead. Set the function switch to ACV. Never try to measure any voltage more than 30V AC on DC source bias. Note: Mylar is a registered trademark of E.I Dupont de Nemours and Company, Inc. 3-PHASE AC VOLTAGE MEASUREMENT We designed this meter to measure household AC voltage. When measuring 3-phase circuits line-to-line, the value of the voltage is actually higher than the rated line-to-ground 3-phase voltage. It is important that you do not exceed the maximum RMS AC rating of this meter - 750 V AC. To find the RMS voltage line-to-line on a 3-phase line, multiply the rated line- to-ground voltage by the square root of 3 (approx. 1.732). For example, on a 480-volt 3-phase line (480V line-to-ground), the total available voltage line-to-line is 480 x 1.732, or about 832V AC. This exceeds the rating of this meter. Severe damage and a dangerous shock hazard could result if you connect the meter to the circuit. Because of the dangers inherent in the measurement of three-phase circuits, we strongly recommend against the use of this meter for such applications. DC CURRENT MEASUREMENT To measure current, you must break the circuit and connect the leads to two circuit connection points. Never connect the leads across a voltage source - doing so can blow the fuse in the meter or damage the circuit under test. The maximum input limit for DC current measurement is 200mA. 1. Set the function switch to DCmA. 2. Plug the black test lead into the -COM jack and the red test lead into the left +diode/kohm/DCmA jack. 3. Remove power from the circuit under test and then break the circuit at the appropriate point. 4. Connect probes to the circuit in series. DO NOT APPLY VOLTAGE TO THE INPUT TERMINALS WHILE THE FUNCTION SWITCH IS IN THE DCmA POSITION. THE CONNECTION MUST BE IN SERIES WITH THE CURRENT. 5. Apply power and read the current. If the measured current's polarity is negative, the minus sign appears before the value. NOTE: The DCmA range is fuse-protected. If the meter does not show a reading in this range, check the fuse. RESISTANCE MEASUREMENT The resistance measuring circuit compares the voltage gained through a known resistance (internal) with the voltage developed across the unknown resistance. So, when you check in-circuit resistance, be sure the circuit under test has all power removed (all capacitors fully discharged). The measuring unit shows the meter's range or distinguishes between 200 ohm and 200 kohm. 1. Set the function switch to the kohm position. NOTE: With no resistance connected across the test leads (resistance infinite), 10.00 Mohms with a blinking 1 appears on the display when you set the function switch to kohm. This is normal. 2. Plug the red test lead into the left +diode/kohm/DCmA jack and the black lead into the -COM jack. 3. Connect the probes across the circuit to measure. For resistance of about 1000 kohm or more, the display might take a few seconds to stabilize. This is normal for high resistance readings. NOTES: Your meter has a circuit to protect the resistance circuit from over-voltage (750V AC, 1 minute). However, to prevent acciden- tally exceeding the rating of the protection circuit and to ensure the correct measurement, never connect the probes to a source of voltage when you set the function switch to the kohm or diode check position. The current applied during resistance measurements could damage some devices. The table below lists the voltage and current available for each range. Range A* B** C*** 200 ohm 1.5 V 150 mV 650 microA 2 kohm 0.65 V 180 mV 100 microA 20 kohm 0.65 V 300 mV 23 microA 200 kohm 0.65 V 350 mV 3 microA 2000 kohm 0.65 V 360 mV 0.3 microA * A is the open-circuit voltage at the jacks in volts. ** B is the voltage across a resistance equal to a full-scale value. *** C is the current through a short circuit at the input jacks. All values are typical. DIODE CHECK FUNCTION This function you check diodes, transistors, and other semiconductors for opens, shorts, and normal operation. 1. Set the function switch to diode. The meter automatically sets the range to 2V. With no semiconductor connected to the meter, the display shows about 1.1, which is the open-circuit voltage. CAUTION: Do not connect the test leads to a source of voltage when you set the function switch to the diode check position. 2. Plug the red test lead into the left + diode/kohm/DCmA jack and the black lead into the -COM jack. 3. Remove power from the circuit under test. 4. Connect the probes to the semiconductor device you want to check and note the meter reading. If the display shows some value, for example, 0.2 for a germanium diode and 0.5 for a silicon diode, the device is good. If the display shows about 1.1, try reversing polarity. Then, if the display shows a value other than 1.1, the device is good. If the display still shows around 1.1 after you reverse the polarity, the device is open. If the display reading is very small or zero when you reverse polarity, the device is shorted. NOTE: You cannot check LEDs because the typical forward voltage for an LED is about 2.0 V. (br/all-06/05/95)