CAPACITORS-TWINSOften, in order to work in a range of electrical oscillations of sound frequencies it is necessary to select the same capacitors. This and various or balanced bridge circuits, and is identical (for electrical options) the channels of a stereo or Quad amplifiers…

In the simplest case, the selection of containers can be done by connecting the “common” wire avometr (tester) and a sound generator between them. Then the investigated capacitor should be connected between the “phase” wires. Avometr should be prepared for the measurement of AC voltage in the range of 0.1—1 V output parameters of ZG should be installed so that the indications of pointer indicator accounted for 0.4—0.7 In (at the named site and scale more linear, and the accuracy of the measurement above).

When everything is prepared, by replacing the capacitors in the measuring circuit and tracking readings avometr (and they should be identical at equal capacities) is determined by the equality of the capacitances of the test capacitors or difference: with less capacitance deviation of the instrument pointer will be smaller and Vice versa. When open condenser avometr will not show any voltage, and with the closure (or strong contrast capacity in a big way) — the needle will go overboard.

Dial isometry, generally have lower limits of an expanded work area in the frequency plan applicable for such measurements. The accuracy of the selection of identical containers will affect the stability of frequency and output voltage of the sound generator, the setting accuracy of the arrow of avometr risks on one of its scales (and not necessarily to this scale has been used AC voltages). As indicator (avometr) try to use a digital multimeter. If you find that it is able to operate at low AC voltages and elevated (relative to the commercial 50 Hz) frequencies, the accuracy of matching tanks with it even increase.


Accuracy in the selection of capacitors of the same capacity is guaranteed by the identity of the relevant readings avometr and sound generator

The accuracy in the selection of capacitors of the same capacity is guaranteed by the identity of the relevant readings avometr and sound generator

The rocking of the instrument pointer may indicate the instability of the output voltage of the sound generator or modulation of the signal voltages low of frequencies as amplitude and frequency. Not excluded also the manifestation of the “flicker” of a controlled size, i.e. the chaotic it changes over time. Of course, the use of such capacitors in critical circuits is not recommended.

If too much “squeeze” and you will have the same “hardware conditions” is a more accurate capacitance measurement can be performed using a reference capacitor and a calibration table of scale avometr. And for a change of the measuring range is quite acceptable here “certdecoder” frequency switching signal issued by the sound generator.

Stability requirements Foutput and VOUT generator remain in force. The limits of the capacity measurement depends on the parameters of the sound generator (output voltage and frequency) as well as from stray capacitance of the connecting wires and is possible at frequencies up to 15-30 kHz.

V. BESEDIN, Tyumen

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