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OPERATING AND TESTING THE MULTIMETER

CAUTION:

When measuring an unknown voltage or current, always start with the range switch set to the

highest scale.  Then, if necessary, move the range switch down until the meter reads in the middle or right

half of the dial.

Checking your multimeter for proper operation is fairly easy.  Of prime importance is knowing which scale

is read for each setting of the range switch.  DC voltage is read on the dial immediately below the meter

mirror.  This dial is marked with three scales with full scale readings of 10, 50 and 250.  The 0-10 volt scale

is used for DC voltage ranges of .1, 10 and 1000VDC.  The 0-50 volt scale is used for DC voltage ranges of

.5 and 50VDC and the 0-250 volt scale is used for DC voltage ranges of 2.5 and 250VAC.  The readings taken

on these scales must be multiplied by the proper scale factor.  For example, when the range switch is in

2.5VDC, a full scale reading on the 0-250 volt scale is actually 2.5 volts.  You should therefore multiply you

reading by .01 (move the decimal point 2 places to the left).  DCmA are read using the same three scales

as DC volts.

AC volts are read on the red dial marked ACV using the same 0-10, 0-50 and 0-250 scales as used for DC

volts.  AC volts may also be read in decibels using the dB scale.  The reference voltage (0dB) for the dB

scale is .775 volts.  This voltage across 600 ohms dissipates 1mW of power.  When dBs are read with the

range switch at 10ACV, the dB scale is read directly.  With the range switch at 50ACV add 14dB.  With the

range switch at 250ACV add 28dB and at 1000ACV add 40dB.

Ohms are read on the top scale.  Multiply the reading by the appropriate factor 1, 10, 1K or 10K as indicat-

ed by the range switch.

If you are new to reading analog meter scales, assemble and try the Dial Scale Reading Exercise included

with this kit.

Before starting tests, set the meter needle to zero .  The zero adjust screw is located on the meter face next

to the base of the needle.  With no test leads connected, slowly turn this screw until the needle points to

zero on the 0-10 scale immediately below the meter mirror.  We will now test each meter function.  If the

meter should fail to perform as indicated, refer to the troubleshooting section for assistance.

DC Voltage Test

1) Plug the red test lead into the positive (+) socket, and the black lead into the --COM socket.

2) Set the range switch to 2.5VDC.

3) Connect the red lead to the positive side of a 1.5V battery (you may remove and use one of the 1.5V bat-

teries from the meter).  Connect the black lead to the negative side of the battery.  The meter should

read about 150 on the 0-250 scale.  Move the decimal point 2 places to the left to obtain 1.5VDC.

4) Set the range switch to 10VDC.  The meter should read 1.5 on the 0-10 volt scale.

5) Set the range switch to 50VDC.  The meter should move about 1 1/2 small divisions on the 0-50 volt

scale.

Ohms Test

CAUTION:

When measuring ohms, be sure that there is no voltage across the circuit being tested.

1) Plug the red test lead into the positive (+) socket, and the black lead into the --COM socket.

2) If you removed the 1.5 volt battery from the multimeter for the DC voltage test, replace it now.

3) Set the range selector switch to X1.

4) Short the test leads together and adjust the 

ADJ pot for a zero reading on the ohms (top) scale.

5) Connect the test leads to a known resistor between 1 and 100 ohms and observe the meter reading.

Multiply by the scale factor to obtain the resistance.

6) Set the range switch to X10 and repeat steps 4 and 5 using a 10 to 1K ohm resistor.

7) Set the range switch to X1K and repeat steps 4 and 5 using a 1K to 100K ohm resistor.

8) Set the range switch to X10K and repeat steps 4 and 5 using a 10K to 1M ohm resistor.

 

Summary of Contents for M-1150K

Page 1: ...ANALOG MULTIMETER MODEL M 1150K Assembly and Instruction Manual Elenco Electronics Inc Copyright 1995 Elenco Electronics Inc Revised 1997 REV D 753012...

Page 2: ...black yellow brown 174031 r 1 R16 6 75M 1 1 2W blue violet green yellow brown 176731 r 1 R8 15M 1 1W brown green black green brown 181532 r 1 R1 680 Pot 191311 r 1 R25 10K Pot 191515 NOTE All fixed re...

Page 3: ...be heated sufficiently so that the solder flows freely Apply the solder simultaneously to the component lead and the component pad on the PC board so that good solder flow will occur Be sure that the...

Page 4: ...gend Band r R1 680 Pot see Figure A r D2 2CZ82P Diode see Figure C r R18 2K 1 1 4W Resistor red black black brown brown r R24 18K 1 1 4W Resistor brown gray black red brown r R19 44K 1 1 4W Resistor y...

Page 5: ...own r R7 4M 1 1 2W Resistor yellow black black yellow brown r R6 800K 1 1 4W Resistor gray black black orange brown r R5 150K 1 1 4W Resistor brown green black orange brown r R3 5K 1 1 4W Resistor gre...

Page 6: ...of grease on top of the spring r Place a ball bearing on top of the spring and carefully push it down into the housing r Holding the bearing in place insert the housing into the case as shown in Figur...

Page 7: ...r Install the the two AA batteries in the battery compartment Be sure to observe the polarity markings on the bottom of the battery compartment r Connect the battery snap to the 9 volt battery and pl...

Page 8: ...the 2 5V scale 155 on 250V scale Shunt Wire Calibration To calibrate the shunt wire you will need a 5A current source like a 5V power supply and a 1 25 watt resis tor If a 5A source is not available...

Page 9: ...ck resistors R24 R25 and R2 through R9 for cor rect values and good solder connections No AC voltage reading 1 Check for open fuse Refer to Figure 8 for a better understanding 2 Check diodes D1 throug...

Page 10: ...assemble and try the Dial Scale Reading Exercise included with this kit Before starting tests set the meter needle to zero The zero adjust screw is located on the meter face next to the base of the ne...

Page 11: ...red and the other with a black alligator clip There is a 24K resistor in series with the black wire on the double test lead To measure the hFE beta of an NPN transistor proceed as follows 1 Plug the...

Page 12: ...ng of the meter is a very important factor to be considered when measuring the voltage of a high resistance circuit Take the example where two 1M resistors are connected in series across a 9V bat tery...

Page 13: ...s is compared to the external resistor in a series circuit The current is supplied by the 3V battery on the X1 X10 and X1K ranges On the X10K range a 9V battery is placed in series with the 3V battery...

Page 14: ...t and the lower the effective resis tance The meter reads this resistance and the hFE of the transistor may be read on the hFE scale Figure 13 Specifications Measurement Ranges Accuracy Remarks DC Vol...

Page 15: ...SCHEMATIC DIAGRAM 14...

Page 16: ...Elenco Electronics Inc 150 W Carpenter Avenue Wheeling IL 60090 847 541 3800 http www elenco com E mail elenco elenco com...

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