How to detect resistors by a pointer multimeter?

l  A method of detecting resistors on-the-circuit by a pointer multimeter.

First, scope of application.

The so-called on-the-road detection refers to the non-live measurement of the components in the circuit on the printed circuit board (note: the circuit must not be charged, but also to the capacitance and other energy storage components discharge). It is a rough measurement when the circuit principle is analyzed in detail and it is estimated that a fixed resistance is likely to be damaged. After a certain amount of experience has accumulated, this kind of measurement can be helpful to the maintenance.

Second, the detection method.

when one of the 10ko fixed resistors in the actual circuit is suspected to be burned out, the multimeter is placed in the Rx1k block, and the red and black pens are short connected and then adjusted to zero. When the resistance is determined that there are no components, such as the General Assembly capacitance or inductor, the multimeter is placed in the Rx1k block. Two pens are connected to the two pins of the 10k0 resistance, and if the resistance indicated by the pointer is close to (generally lower) 10kq, the possibility of the resistance failure can be ruled out; If the indicated resistance value is too different from the 10kq resistance, the resistance may be damaged. At this point, any of the pins of the resistance may be disconnected from the circuit for open-circuit measurement to confirm.

Third, issues that need to be explained.

When measuring a fixed resistance, the following principles shall be followed:

(1). Open-circuit measurement first zero, two hands can not be combined resistance.

(2). In the rough measurement of discharge on the road, the head of the personnel table is safe.

l  The method of measuring resistance by half voltage method is used in direct current voltage protection of pointer multimeter.

The schematic diagram of the method for measuring resistance using a multimeter DC voltage stop half voltage is shown in figure 4 / 2. In order to improve the accuracy of measurement, R adopts standard resistance box. If R is adjusted so that the indicator of the DC voltmeter equals half of E, the measured resistance Rx is equal to the reading on R.