Voltmeters and ammeters are commonly used tools in electronic measurements to measure voltage and current in electrical circuits. Here's a detailed look at how to use them and how to judge failures:
Voltmeter Tips:
1.Choose the appropriate range: A voltmeter usually has multiple ranges, and the appropriate range is selected based on the estimate of the voltage being measured. Selecting a range that is too small can lead to overflow, and choosing a range that is too large may reduce the accuracy of the measurement.
2.Properly connect the voltmeter: Connect the red measuring lead of the voltmeter to the positive pole of the voltage to be measured in the circuit, and the black measuring lead to the negative pole or location of the voltage to be measured in the circuit. Make sure the connection is correct and avoid short circuits or misconnections.
3.Pay attention to the polarity of the voltage: The voltmeter is polar, so you need to pay attention to the positive and negative polarity of the voltage when measuring the DC voltage. If the voltmeter shows a negative value or is contrary to expectations, it is possible that the measurement leads are connected in reverse.
4.Stable reading: When measuring voltage, the measurement lead of the voltmeter should be kept stably connected and avoid shaking or loosening to ensure the accuracy of the reading.
5.Be aware of the measurement error: voltmeters have their own measurement error, so when making accurate measurements, the error can be reduced by averaging multiple measurements.
Tips for using ammeter:
1.Select the appropriate range: The ammeter usually has multiple range steps, and the appropriate range range is selected based on the estimate of the current being measured. Choosing too small a range will cause the ammeter to burn out, and choosing too large a range may reduce the accuracy of the measurement.
2.Properly connect the ammeter: connect the red measuring lead of the ammeter to the positive terminal of the current to be measured in the circuit, and the black measuring lead to the negative pole of the current to be measured in the circuit or to the path of the connected current. Make sure the connection is correct and avoid short circuits or misconnections.
3.Pay attention to the direction of the current: The ammeter is directional, so you need to pay attention to the direction of the current when measuring the DC current. If the ammeter shows the opposite direction as expected, the measurement leads may be connected in the opposite direction.
4.Prevent overload: The ammeter has a certain rated current range, and exceeding the rated current will cause the ammeter to burn out. Before measuring, make sure that the current to be measured does not exceed the rated current range of the ammeter.
5.Pay attention to measurement errors: ammeters have their own measurement errors, so when making accurate measurements, the error can be reduced by averaging multiple measurements.
How to judge the fault:
1.Check the power supply: First, check whether the power supply of the circuit is normal, including whether the voltage is stable, whether the power cord is well connected, etc. Use a voltmeter to measure the power supply voltage to ensure that the power supply is working properly.
2.Check the circuit connection: Check whether the connection of the circuit is loose, poor contact, or short circuit. Use a voltmeter to measure the voltage at each connection point of the circuit to ensure that the circuit is properly connected.
3.Check for component failures: If a component in a circuit is likely to fail, you can use a voltmeter and ammeter to measure whether the component is working properly. For example, the resistance of a resistive element can be measured, the forward voltage drop of a diode can be measured, and so on.
4.Check the direction of current flow: Use an ammeter to measure the direction of current flow in the circuit to make sure that the current is in the correct direction. If the current direction is opposite to what is expected, it is possible that the circuit is connected incorrectly or the component is damaged.
5.Compare measurements: When troubleshooting, you can use a voltmeter and an ammeter to make multi-point measurements and compare the measurements to a working reference circuit. If there is a noticeable difference, there may be a fault.
When using voltmeters and ammeters, follow safe operating procedures to avoid accidents such as electric shock or short circuit. In addition, different models of voltmeters and ammeters may have different characteristics and operation methods, it is recommended to refer to their user manuals or operation guides for more accurate usage tips and safety precautions. Workplace Skills Competition