MX-25 302 User’s guide for 3 1/2 digits multimeter Description: 1.1 General description 2 Display: ½ digits liquid crystal display, with 26 mm characters max. displayable …1999 Polarity: Automatic negative polarity display Null: Automatic Measuring method: A/D converter Measurement rate: 3/seconds Overload Display: only the “1/-1” symbol is shown symbol is shown on the display Low Battery : the battery Security requirements: CE EMC/ LVD. The instrument corresponds to the IEC1010 standard.
2.1 Electronic characteristics Punctuality +/- (displayed value’s rate(%) + the number of the digits) 23 +/-5 C°, if the humidity is lower than 75%.
Resistance Measuring range 200Ω 2Ω 20 Ω 200 Ω 2MΩ 200 M Ω Accuracy +/- (0,8%+5) +/-(5,0%(rdg-10) + 20) Resolution 0,1 Ω 1Ω 10 Ω 100 Ω 1kΩ 100 k Ω Accuracy +/- (0,8% + 3d) +/- (1,2% + 4d) +/- (2,0% + 5d) Resolution 10 uA 100 uA 10 mA +/- (0,8% + 3) output voltage : <3V Overload protection: 250 V DC/AC RMS DC Current Measuring range 20 mA 200 mA 20 A Max : 200 mV Max input current: 20A (maximum 10 seconds) Overload protection: 0,2 A/250 V “F” fusion 20A measuring range not ensured! 4
AC current Measuring range 20 mA 200 mA 20 A Accuracy +/- (1,0% +5) +/- (2,0% +5) +/- (3,0% +10) Resolution 10 uA 100 uA 10 mA Accuracy +/- (2,5% + 20) Resolution 10 pF 1 nF 100 nF Max.
Temperature Measuring range -40 C° – 1000 C° Accuracy +/- (1,0%+3) < 400 C° +/- (1,5%+15) > 400 C° Resolution 1 C° Description Open circuit voltage measurement Test mode Open circuit DC current approx.
Transistor hfe” test Function hfe Description … the transistors electric power (0-1000) (All the types) Test mode Basis current around 10 uA V ce around 3V 2. Use of the device 1. Check the 9 V battery, turn Power On position. If the battery exhausted, the symbol appears on the display. 2. The signs next to the wires are showing, that the input voltage or current shouldn’t be higher than the correct value. In this way you can protect the internal circuits from the damages. 3.
2.2 Measure of DC and AC current 1. connect the black wire in to the “COM”, the red in to the “mA” (max . 200mA) or the “20A” wire for measuring 200mA – 20A. 2. Switch the Function button in to the right measure range. 3. Connect the wires tightly to the (DC/AC) source for the measure. 4. Between the measuring range of 200 mA and 10A ( current) connect the red wire to the “20A” to measure it. Note: a.
2.4 Capacity measure 1. Set the function switch to the F position. 2. Connect the black test lead to the (-) jack „COM” and red lead to the (+) jack „mA”. 3. Connect test leads across the capacitor under measurement and be sure that the polarity of connection is observed. Note: 1. If the value of the measurable resistance over helming the value of the maximum measurable level, and if the instrument overloaded, (“1” or”1”) choose a higher measure range. 2. Unit: 1uF=103 nF 1nF=103 pF 3.
Note: 1. This unit uses a special temperature measuring sensor. 2.7 Transistor hfe Test Turn the switch to hfe. 1. Connect the sensor to the COM and mA ports. 2. Put the transistor into the appropriate socket, depending on the transistor being NPN or PNP. 3. The display shows the current amplifying factor of the transistor IB= 10uA, VCE =3V. 2.8 Frequency measurement 1. Connect the instrument cable or shielded wire to the COM and to the V/Ω/Hz/C port. 2.
4. Warning 1. When measuring 32 V DC / 25 V AC be sure that no cables are connected to the current measuring socket and the main switch is not in diode or resistor testing mode.Always make sure that you connected the cable to the right socket for its voltage. 2. Be cautious when measuring voltage higher than 50V, especially in the case of high current. 3. Do not connect the unit to “live” circuits. 4. When measuring current, turn off the voltage before you connect the multimeter.
4.2 Servicing the device 1. Changing the battery (one 9V battery is required) a. Switch off the unit and disconnect every external circuit. Disconnect the instrument cable from the socket. b. Remove the screws then the cover on the bottom side. c. Remove the flat battery and insert a new one from of same type ( Standard 9V battery). 2. Switching a fuse (5x20 mm ,200 mA / 250 V “F” labeled fused are used) a. Switch off the unit and disconnect every external circuit.
