SU319992A1 - DEVICE FOR FIXING ELECTRIC VALUES - Google Patents

Description

The invention relates to devices for fixing electrical quantities containing a measuring transformer, a rectifier, a starting relay, a reference memory capacitor, a capacitor for discrete cyclic discharge, an additional relay, a pulse counter.

To obtain a uniform reference scale, the proposed device is equipped with a nonlinear element, for example, a transistor, in the emitter circuit of which a capacitor is connected for discrete cyclic discharge, and in the output circuit - an executive relay and a pulse counter.

The drawing shows a circuit diagram of the proposed device.

The device contains a measuring transformer 1, a rectifier 2, a reference capacitor 3 1Л 4, a transistor 5 of the pp type, a relay 6 and a pulse counter 7.

When a pulse occurs, an external start relay is activated and its contact 8 connects the reference storage capacitor 3 with a capacity of Ci to the rectifier 2, and contact 9 bypasses the capacitor 4. The capacitor 3 receives a charge C / meas-C where C / H3M Ki-Of - at voltage pulse latching;

(2-1f - during pulse fixation. / F - respectively, the amplitudes of the fixed voltage and current pulses.

After a short circuit, the starting relay returns. The capacitor 3 is disconnected from the rectifier and by the contact 9 of the starting relay, through the collector-emitter junction of transistor 5, an uncharged reference capacitor 4 is connected to it, which is much smaller than the capacitor 3 of the capacitance Cz.

Capacitor 4 is charged from capacitor 3, and the charge on capacitor 3 decreases to

,, - (U, -C, q,), where Uz-Cz is the total charge on the capacitor

Cr

qo is the part of the charge on the condenser Cr from the voltage source Lo. and., - C,

-Tut

where p is the current gain of transistor 5.

The capacitor 4 at the time of closing of the transistor 5 is charged to the voltage Uy.

The voltage on the capacitor 3 after the first cycle:

//// ./ // Cz P / g

17 Uj - ill

GI p + 1

During charging of the capacitor 4. a relay 6 is activated, which, with a delay that is sufficient to terminate the charge of this capacitor, by contact 10 disconnects the capacitor 4 and short-circuits it, ensuring full discharge.

Contact 11 of the relay 6 includes a pulse counter 7, counting the first pulse. Next, the relay 6 returns, and the discharged capacitor 4 is again connected to the capacitor 3. The capacitor 4 is charged again, the voltage on the capacitor 3 decreases to

, J - 2-.-1-.

and „p +1

Then relay 6 is activated, the counter counts the second pulse, the capacitor discharges.

The discrete cyclic discharge of the storage capacitor 3 continues until the voltage on it after the next charge of the capacitor 4 decreases to the threshold value Un, at which the new pulse of the charging current of the capacitor 4 is no longer

is able to activate the relay 6. Therefore, the number of pulses N, counted by the counter, can be found from the equation:

N- С,

p - ism

-CJ.

+ 1

 meas. Ci 1 + 1

l

WITH

/ "

The number of pulses is linearly dependent on the value of f / ism, and the device’s reading scale is uniform and can be scaled as a scale in a voltmeter or ammeter.

Invention

A device for fixing electrical quantities, comprising a measuring transformer, a rectifier, a starting relay, a reference storage capacitor, a capacitor for discrete cyclic discharge, an executive relay and a pulse counter, characterized in that, in order to obtain a uniform reference scale, it is provided with a non-linear element, for example, a transistor, in the emitter circuit of which a capacitor for discrete cyclic discharge is connected, and in the output circuit - an executive relay and a pulse counter.

/ g

+ J3