The video discusses the top 10 mistakes to avoid when using a multimeter. These mistakes include:
1. Measuring small quantities over a large measurement range, which can lead to inaccurate results.
2. Measuring large values on a small range, which can cause the device to go off scale or be damaged.
3. Not discharging capacitors before measuring their capacitance, which can damage the device.
4. Switching the multimeter function without disconnecting the probes from the circuit.
5. Measuring current in an electrical circuit without checking the expected value, which can cause damage to the device.
6. Not turning off the voltage when measuring resistance in electrical appliances.
7. Not removing the transistor from the socket when switching from transistor testing to AC voltage measurement.
8. Measuring current exceeding 200 milliamps for more than 15 seconds, which can cause damage to the device.
9. Measuring the current of asynchronous electric motors at startup, which can cause damage to the device.
10. Testing white LEDs for serviceability using a multimeter, which is not adequate due to the high forward voltage drop and limited current delivery of the multimeter.
The video emphasizes the importance of following proper procedures and precautions when using a multimeter to avoid damage to the device and ensure accurate measurements.
Here are the key facts extracted from the text:
1. Measuring small quantities over a large measurement range can result in inaccurate results.
2. The correct range for measuring a value should be selected so that the value is not at the beginning of the range, but rather close to the middle.
3. A resistor's actual resistance may not be exactly equal to its nominal value due to a tolerance of plus or minus five percent.
4. Measuring large values on a small range with a multimeter can result in an "off scale" reading and potentially damage the device.
5. Measuring voltage on a low range, especially in sockets, can damage the device.
6. A multimeter should be set to a range with a reserve of 750 volts when measuring voltage.
7. Capacitors should be discharged before measuring their capacitance to avoid damaging the measuring device.
8. A jumper or other device can be used to discharge a capacitor before measuring its capacitance.
9. Measuring current in an electrical circuit can damage a multimeter if the expected value exceeds 200 milliamperes.
10. The milliampere measurement terminal should not be used to measure currents exceeding 200 milliamperes.
11. A multimeter's measuring circuit can be damaged if the current being measured exceeds 200 milliamperes for more than 15 seconds.
12. Asynchronous electric motors can consume a current 5-7 times more than their rated value at startup, potentially damaging a multimeter.
13. A toggle switch or circuit breaker can be used in parallel with a multimeter to measure the current consumed by an electric motor without damaging the device.
14. White LEDs cannot be reliably tested using a multimeter's diode testing function due to their high forward voltage drop and current requirements.
15. A multimeter's measuring circuit is not capable of delivering significant currents, exceeding 10 milliamps.
16. Red and green LEDs can be tested using a multimeter's diode testing function, but white LEDs may not be reliably checked.
17. Most multimeter breakdowns occur when the user forgets to switch the device from one function to another or fails to rearrange the probes correctly.