What is practical about using a multimeter to measure resistance?
Multimeter resistance block function.
1, coil class: 1 two pens, measure the coil ends, the role is to determine whether the coil is disconnected. Conductivity buzzer will call, not conductivity, buzzer will not call.
A pen at one end of the coil, the other pen in the ground broken, measuring the coil resistance to ground, to determine whether the coil insulation is burned.
2 contact type, such as contactor, intermediate relay main contact, vice contact. Meter pen on both ends, measure whether the contact is good, judge whether the contactor should be replaced.
3 Diode / triode. Measure its resistance, diode has a unidirectional conductivity, you can judge the diode's positive and negative poles, you can also judge the diode is good or bad, whether it is reverse breakdown.
Multimeter resistance block also has a role is to measure the voltage of the diode conduction. Select the gear to the resistance block, in the switch, is to measure the diode conduction voltage, silicon tube is 0.7V, germanium tube is 0.3V. to judge the quality of the diode is good or bad.
Note that when measuring resistance with a multimeter, the machine must not be charged. Power off to measure resistance.
The above is only the use and role of the multimeter resistance block.
More commonly used is the voltage block.
With the multimeter's voltage block, a pen on the place you want to measure, the other pen on the reference point, usually ground or metal casing, to measure the voltage to meet the requirements of our design. The voltage between the fire wire and the earth wire is 220V, and the voltage between the fire wire and the zero wire is also 220V. the voltage between the fire wire and the fire wire is 380V. satisfying these three figures means that the incoming wires are normal.
Multimeter ohm gear, is the most used one gear
We are in the maintenance or check the circuit, components, generally use the ohm gear, summed up, commonly used mainly the following functions or uses:
1, measuring the line on and off, such as motor coil measurement, this case, many also use the buzzer gear measurement
2, measuring the circuit, component resistance, used to calculate its power and other parameters, such as our furnace, according to the measured resistance to calculate its heating power.
3, used to determine the component's good or bad, for example, a chip or component, a normal resistance between the two legs is 100 ohms, the actual 1K, or infinity, is certainly a bad component, but also for example, thermistor, measure the resistance value of his ends, does not change with the temperature changes, then the thermistor should be bad!
4, measure the actual resistance of the circuit resistor, some colour ring resistor colour ring can not be seen, but also to verify the actual resistance of the colour ring resistor!
