In this tutorial, you will learn the basics of using an analog multi-tester or multi-meter. We are using a SANWA-360TRF Model as our preference. If you already have a multi-tester different from this one, don’t worry any model is fine.
We will guide you into a simple way of learning on how to measure:
a) DC Voltage – A voltage in the battery (dry cell or wet cell) or from a rectified power supply. It is measured using a DCV (Dc voltmeter).
b) AC Voltage – A voltage in the mains-outlet (220 Vac) or from unrectified power supply. It is measured using an ACV (Ac voltmeter).
c) Resistance – Resistance of a resistor, semiconductor and a wire or coil of wire. It is measured using an Ω ( Ohmmeter).
d) Current – A small current flowing in the circuit. It is measured using DCA (Dc ammeter).
In this image you will see the corresponding names of its parts to get familiar with.
You may have noticed in this image (in the range selector area), It is subdivided primarily into four main sections.
1) ACV – is an AC voltmeter (enclosed with a red bracket) on upper-right side. It has 4 range of selections.
Here you can select:
a. 10 – Select this range if the voltage to be measured is less than 10 volts ac.
b. 50 – Select this range if the voltage to be measured is less than 5o volts ac but more than 10 volts ac.
c. 250 – Select this range if the voltage to be measured is less than 250 volts ac but more than 50 volts ac.
d. 750 – Select this range if the voltage to be measured is less than 750 volts ac but more than 250 volts ac.
2) DCV – is a DC voltmeter (enclosed with a white bracket) on upper-left side. It has 6 range of selections.
Here you can select:
a. 0.1 – Select this range if the voltage to be measure is less than 0.1 volts dc. You may have noticed how this range intersects with DCA (Dc ammeter section). Therefore it can be also used as a a dc ammeter but only within this range.
b. 0.25 – Select this range if the voltage to be measured is less than 0.25 volts dc but more than 0.1 volts dc.
c. 2.5 – Select this range if the voltage to be measured is less than 2.5 volts dc but more than 0.25 volts dc.
d. 10 – Select this range if the voltage to be measured is less than 10 volts dc but more than 2.5 volts dc.
e. 50 – Select this range if the voltage to be measured is less than 50 volts dc but more than 10 volts dc.
f. 250 – Select this range if the voltage to be measured is less than 250 volts dc but more than 50 volts dc.
g. 1000 – Select this range if the voltage to be measured is less than 1000 volts dc but more than 250 volts dc.
3) DCA – is a DC ammeter (enclosed with a white bracket) on lower-left side. It has 4 range of selections.
Here you can select:
a. 50μ – Select this range if the current to be measured is less than 50 microampere.
b. 2.5m – Select this range if the current to be measured is less than 2.5 milliampere but more than 50 microampere.
c. 25m – Select this range if the current to be measured is less than 25 milliampere but more than 2.5 milliampere.
d. 0.25 – Select this range if the current to be measured is less than 250 milliampere but more than 25 milliampere.
4) Ω – is an ohmmeter (enclosed with a white bracket) on lower-right side. It has 4 range of selections.
Here you can select:
a. x1 – Select this range if the resistance to be measured is very low, ranging from 0 ohms (short circuit) to 1kΩ.
b. x10 – Select this range if the resistance to be measured is ranging from 10Ω to 10kΩ.
c. x100 – Select this range if the resistance to be measured is ranging from 100Ω to 100kΩ.
d. x1k – Select this range if the resistance to be measured is ranging from 1kΩ to 1MΩ.
There are several practice that you need to know while making it as a habit when using a multi-tester.
1. Before using a multi-tester, make sure the pointer points to infinity position. It should look exactly like the image above.
By default, it should point exactly to infinity scale since it was properly set by the manufacturer. If not, slowly turn the “zero position adjuster” until it points exactly to infinity position.
2. Before using an ohmmeter (it doesn’t matter what range you have used), always short the test pins (red and black) to test if the pointer points to zero resistance. If not, turn the “zero ohm adjuster knob” until it points to zero.
3. Be careful in using an ohmmeter – make sure you are doing resistance measurement and not voltage measurement. Ohmmeter’s internal circuit is powered by a 3v battery. Accidental voltage measurement will amplify the current inside the circuit and can cause severe damage.
4. Before doing voltage measurement, be sure to identify whether it is an AC (alternating current) or DC (Direct Current) voltages.
5. Before doing voltage measurements, make sure you have selected the correct range so that the voltage to be measured is lower than the range being selected.
These are the basic information on how to use the multi-tester or multi-meter. On our next article, you will learn how to read the scale on voltage, current and resistance values. If you think i missed something or messes something up. Please let me know and i’ll gladly make an update right away.
Fix it Phillip 