Universal measuring instruments

Details Parent Category: House Hits: 22007

Measurements of basic electrical quantities

Bridge circuits

Universal measuring instruments

Such devices are called avometers and also testers (from the English word test - trial, test). With their help, they check the voltage, current, resistance of wire and non-wire resistors, the integrity of the fainting of inductors and transformers, leaks in capacitors, as well as the compliance of harnesses, printed circuit boards and other devices with connection diagrams and circuit diagrams.

Versatile instruments have several measuring ranges with different limits. When switching ranges, various shunts or additional resistors are connected to the dial gauge, due to the pnm the measurement limits change. One or another range of the device must be selected based on the parameters and the required measurement accuracy for each specific scheme.

The upper panel of the plastic housing of the device contains controls and devices for connecting measuring shunts.

For most instruments, the operating frequency range for AC operation is 45 - 10,000 Hz. Some of the devices, in addition to voltage and current, can measure the capacitance of capacitors and the relative levels of alternating voltage, as well as the parameters of transistors.

For example, the combined instrument C4328 is used for vehicle maintenance. In addition to the usual parameters, they measure the angle of the closed state of the breaker contacts and the crankshaft speed of a four-cylinder passenger car engine having 12 V electrical equipment with a minus battery connected to the "ground".

The combined device Ts4341 uses to measure the static characteristics of low and medium power transistors: current transfer coefficient, collector and emitter reverse current, initial collector current. For all measurements (except for resistances at the limit of 5000 kOhm) the Priority is powered by a built-in battery. When measuring at the limit of 5000 kOhm, an external source of constant voltage of 37 - 48 V is required. The operating frequency range of the device when measuring at alternating current is 45 - 20,000 Hz.

When working with universal measuring instruments, it must be remembered that in each range the scale division of the instrument is different and must be determined for each position of the switch knob. In addition, the instrument has different scales for DC and AC measurements. Therefore, depending on the type of current, the counts must be made on the appropriate scales. It is also necessary to ensure the correct installation of the switches that switch operation, otherwise the device may be damaged.

O. Vershinin I. Mironenko

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