You can’t help but know the error-prone points when using a multimeter
Is it easy to measure current with a multimeter? It can be said yes or it can be said no. No matter what you do, you need to be careful. (1) Do not confuse the current measurement method with the voltage measurement method. Because many novices use the same method of measuring current as measuring voltage, directly connect the test leads in parallel to the circuit, so if your multimeter is a non-brand meter, the fuse is burned, and the shunt resistor in the current block shunt must be burned, if it is a digital meter If it is not possible, even the 7106 has to be hung up, but if it is a better multimeter, if the voltage is measured incorrectly with the current block, the voltage signal will be clamped by the current block protection circuit, and the bidirectional limiter diode is clamped at 0.7V. Protect the current block shunt. (2) We know that the method of measuring voltage is to set the multimeter to the voltage stop, then insert the red test lead into the VΩ hole and the black test lead into the COM hole, and then connect the red and black test leads in parallel to the circuit to measure the voltage. The current is just the opposite, that is, If you want to measure current, use the multimeter's current block and choose a proper range. If you don't know the current value, you can choose a larger range to prevent the multimeter from displaying '1' over the range, and then insert the red test pen into the mA hole or 10A hole. Insert the black test lead into the COM hole (the COM hole is called the common end and the black test lead jack), and then disconnect a part of the circuit, and string the red and black test leads into the measurement. That is to say, if you want to measure the current, you must string it into the line for measurement. (3) Computer motherboards generally do not have color resistors. They are called color ring resistors. They usually appear in analog circuits. However, the resistors in computer motherboards are all patches. Use a multimeter to block the resistance to measure the resistance. If you don’t Knowing the resistance value of the resistance under test, you must set it to the highest range of electrical barrier to measure. When measuring, do not touch the metal part of the test pen with your hands, so as not to introduce human body resistance and cause measurement errors.