Principle of Far Infrared Thermometer Performance Index of Far Infrared Thermometer
1.5 volts: This is to measure the power of the 1.5 volt battery, and the display is the voltage
Diode buzzer: It can measure the unidirectional conduction of the diode, and the displayed number is the voltage drop of the diode, in millivolts. The buzzer is used to test the on-off, which is very practical.
Ω: resistance file, be sure to turn off the power when measuring resistance.
HFE: Measure the parameters of the triode, showing the magnification of the triode. There is no test lead for measuring the triode, and there is a triode socket.
Live wire: You can measure the live wire, pinch the black test lead or ground, the one with the HV symbol is the live wire.
V—: DC voltage file, connected in parallel to the tested line, the DC voltage has positive and negative.
V~: AC voltage range, same as above, only positive value.
A~: In the AC current range, you need to connect a multimeter to the circuit under test. Be sure to estimate the current. If you cannot estimate it, use a large range.
A--: DC current gear, same as above.
F: Capacitance gear, remember to discharge when measuring capacitance.
Multimeter usage formula
1. To measure, first look at the gear position. If you don’t look at it, you can’t measure it.
Make it a habit to see if the gear is correct every time you measure
2. Measure without shifting the gear, and shift to neutral after the measurement
Do not switch gears at will when measuring, especially when measuring high voltage and strong current, it is easy to burn out the multimeter.
3. The dial should be level and the readings should be aligned
The pointer multimeter should be placed horizontally, and it should be facing the dial when reading.
4. The measuring range should be appropriate, and the needle deviation is more than half
Estimate the approximate range before testing, and then select the appropriate range. If it is impossible to estimate, measure with a large range first.
5. Measure R without charge, measure C and discharge first
Be sure to turn off the power when measuring resistance, and remember to discharge when measuring capacitance.
6. To measure R, adjust to zero first, then shift to zero
Remember to zero the pointer multimeter when measuring resistance
7. Black and negative should be recorded clearly, and the black in the table should be connected with "+"
Red is positive and black is negative, the positive and negative of the test pen must be distinguished, but the black test lead is connected to the positive pole of the internal battery.
8. The test I should be connected in series, and the test U should be connected in parallel
When measuring current, the multimeter is connected in series to the line under test, and when measuring voltage, it is connected in parallel to the line under test.
9. The polarity is not reversed, one hand becomes a habit
Do not reverse the polarity of the red and black test leads when measuring voltage and current, and develop the habit of one-handed operation.
