SU450343A1 - Converter parameters of the passive electric circuit in the frequency - Google Patents

Description

one

 The invention relates to the field of instrumentation engineering and is intended to automate the process of measuring the parameters of passive electric circuits of various electronic equipment.

A known parameter converter of a passive electric circuit into a frequency comprising an amplifier-limiter, an integrator, the output of which is connected to the input of the amplifier-limiter, and a mutual inductance coil.

However, in the known device it is impossible to convert such a parameter of a passive electric circuit as mutual inductance.

In order to expand the functionality, the proposed converter additionally contains an exemplary inductor and a DC amplifier, the negative feedback circuit of which includes one of the windings of the mutual inductance, the second winding of which is included in the input circuit of the integrator, and the sample inductance is connected between the amplifier output limiter and DC amplifier input.

The drawing shows the proposed Converter.

The device works as follows.

The output of the differential amplifier 2

The limiting device (HFD) 1, covered by deep positive feedback, at the moment of switching on appears a voltage jump of amplitude - EO, which is fed through an exemplary LO inductance LO to the input of a DC amplifier 2 (UPT), in a parallel negative feedback circuit. The coupling of which includes one of the windings LI of the mutual inductance, which has losses, and simultaneously through the voltage divider 3, consisting of resistors Ri and .Rz, to the non-inverting input of the DUO 1. The current in the winding circuit LI is determined by the LO value (coefficientreinforcement of TFC 2 should be quite large)

,

Another winding LZ of the mutual inductance coil possessing the loss of Rn ,, is included in the input circuit of the integrator 4, the input resistance of which must be sufficiently large. Due to the inductive coupling between the windings LI and LZ in the latter, an emf is induced. mutual induction defined by the following expression

 -.f.

Mdi,

dt

"

30 where M - the value of mutual inductance.

(In order for the circuit to work properly, the windings must be turned on –– at all).

The integrator output voltage 4 is equal to

P - - ° .M

with / and -.

where Ti is the integration constant that supplies the inverting input of DUO with "a" 1. At the moment of changing the sign of the voltage difference at the inputs of DUO 1, its output voltage increases abruptly to the value, after which DUO 1 | works similarly, however, the current in the winding L and the output voltage of the integrator 4 vary linearly as a function of time, starting not from zero, but from the values determined by the energy of the magnetic and electric fields accumulated in the previous work cycle, respectively.

Frequency of gene | p1iruyuschih fluctuations at the output of DUO 1 directly proportional to the value of mutual inductance

one

 -

-W,

4LotHK

where K is the transmission coefficient of the divider 3 voltage.

Subject invention

Converter of electric circuit parameters, B frequency, containing amplifier-limiter, integrator, output

which is connected to the input of the amplifier-limiter, and the mutual inductance coil, characterized in that, in order to expand its functional capabilities, it additionally contains an exemplary coil

an inductance and a constant-current amplifier, in the negative feedback circuit of which one of the windings of the mutual inductance coil is included, the other winding of which is included in the input circuit of the integrator, and an inductance coaxial switch is connected between the output of the amplifier and the DC input amplifier .

 L-, / 7,

Output

P

R i

Ij

L7

X

h Z-p Rm

if