Bridge principle and use

Digital bridge is able to measure inductance, capacitance, resistance, impedance of the instrument, which is a traditional customary statement, the earliest impedance measurements with a real bridge method, with the development of modern analog and digital technology, has long been eliminated this measurement method, but the LCR bridge has been called to follow the present.

Digital bridge measurement object for the impedance components of the parameters, including AC resistance R, inductance L and its quality factor Q, capacitance C and its loss factor D. Therefore, the digital bridge is often referred to as a digital LCR meter. Its measurement frequency from the frequency to about 100 kHz. The basic measurement error is 0.02%, generally in 0.1% or so.

DUT for the measured part, its impedance is expressed in Zx, Rr for the standard resistor. Toggle switch can be measured respectively the two voltages Ux and Ur, for a phase quantity relation equation. If the use of phase-sensitive detector (PSD) were measured Ux and Ur corresponding to a reference phase components and quadrature components of the same phase, and then the analog-to-digital converter (A/D) converted to digital quantities, and then by the computer for the complex number of calculations, you can get the composition of the measured impedance Zx value of the resistance and reactance value.

1, power

First of all, the IEC end of the power cord with IEC is connected to the IEC socket at the left rear of the bridge, and the other end is inserted into a suitable power socket, and the boat-shaped switch at the left rear of the bridge is moved, even if the bridge is energized. When energized, the display, range and function indicators light up. The bridge can be automatically placed in the inductance, capacitance measurement gear, parallel equivalent and 1KHz frequency state. Under normal circumstances, the internal circuit can be stabilized after a few seconds of power-up, and measurement can be carried out.

2, the access method of the component under test

1) usually radial lead components can be directly inserted into the combination of test clamp clipboard, and access to special flexible lead components, should be carried out with the help of the clipboard clutch, the clutch is located in the test folder directly under the device.

(2) access to axial lead components, in order to avoid twisting the lead, axial adapter can be used, first of all, the two fittings were inserted into the two ends of the test folder, and then the spacing is corrected to the position of the components suitable for measurement, and then the axial lead components will be inserted into the fittings of the ends of the fittings folder.

(3) in the axial adapter must be quite firmly set occasions, such as in the measurement of a large number of similar components, the need to use the support plate. Installation of the support plate: first of all, the axial adapter adjusted to the appropriate position, and then the support plate suspended above the axial adapter, so that each axial adapter through the slot on the support plate, put the support plate, the fixed screws aligned with the screw holes on the bridge panel, and finally tighten the screws. Note: It is not easy to overtighten the screws during installation.

Note: Although the bridge is able to protect the charging capacitor access test, it is best to discharge the charging capacitor through the appropriate resistance before measurement.