How to check if the circuit is open with using a multimeter?

The range switch of the digital multimeter is set to the position marked with the symbol “●) )”, the red meter pen is inserted into the "V.Ω" socket, and the two meter pens are connected with the two ends of the circuit to be detected. But it should be noted that the detection condition is that the open circuit voltage is about 0.5-0.6 V.

First, the detection of circuit conduction.

If the two points of the detected circuit are on, the buzzer inside the digital multimeter will make a sound when the two meter pens of the digital multimeter are in contact with the two points of the circuit.

Second, the detection of the circuit open.

If the two points of the detected circuit are not working, the buzzer inside the digital multimeter will not make a sound when the digital multimeter two meter pen is in contact with these two points of the circuit.

Third, Detection of where a solder joint leads.

    In the absence of a blueprint reference, if you want to know where a solder joint leads (some electrical wiring is between the inner layers of the circuit board and is often invisible to the eyes), the following methods can be used.

Put the retaining position of the digital multimeter in the buzzer block, then connect a watch pen of the multimeter to the detected pad, and use another watch pen to "scan" the pins of all components on the circuit board, if a buzzer rings, It means that the connected solder joint has been found.

Fourth, the detection of breakdown and short circuit.

When the electrical equipment fault is overhauled, it is often necessary to detect whether the components connected to the positive pole of the DC power supply are short-circuit to the GND, such as the breakdown of the power supply integrated circuit or the power amplifier, etc. When this kind of fault occurs, the most typical characteristic is that the leakage of large current will occur after the power is switched on. The following methods are used to detect such failures with digital multimeters.

Put the digital multimeter baffle in the buzzer block, then put one meter pen of the multimeter with the power supply end of the detected circuit, and use another meter pen to ground. If the buzzer will ring, then there are components that break through the short circuit.

Then keep the table pen connected to the power supply end not moving, use another table pen to touch the pins of the relevant components, and find the components that break the short circuit by the buzzer or not. The detection method is the same as the above.