SU624360A1 - Voltage comparator - Google Patents

Description

The invention relates to measuring and computing equipment and automation, and can also be used in power controllers of arc melting electric furnaces used in ferrous metallurgy for the production of steel and ferroalloys.

A voltage comparison device is known, which contains two matching transformers, the secondary windings of which are connected to the diagonals of two rectifying bridges, two connection resistors connected between the polarized terminals of the rectifying bridges, and a summing resistor. This known device has a low transmission coefficient.

The purpose of the invention is to increase the transmission coefficient. In the proposed device, this is achieved by inserting two transistors and two diodes, one output of each of the communication resistors connected to the collector of the transistor, the second output to the base of the transistor, the emitter of the transistor through the diode | to its base and directly to the output of the summing resistor.

The drawing shows the proposed device.

It consists of matching transformers 1 and 2, rectifying bridges 3 and 4, elements of the internal circuit, for example, connection resistors 5 and 6, connected equipolar output of rectifying bridges, diodes 7 and 8, controllable elements, for example transistors 9 and 10 and a summing resistor 11,

The electrical circuit of the proposed device works as follows.

Claims (2)

In case of equality of alternating voltages on the secondary windings of matching transformers 1 and 2. Not rectifying bridges 3 and 4, connected to the mentioned windings, the values of constant voltages are also equal to each other. Positive potential § Tr of bridge 3, through resistor 5, diodes rectifying bridge 4n resistor 6 is flowing current 3 to the negative potential of rectifying bridge 3, closing to the secondary winding of the connecting transformer Is From the positive potential of the rectifying power 4, through the resistor 6, rectifying diodes bridge 3 and resistor 5 is flowing current L to the negative potential of the rectifier bridge 4, closed on the secondary winding of the matching torsforg gazor 2 With this connection circuit of the rectifying blades) B 3 and 4 there is no effect of the other source from one source at a certain ratio of the compared voltages, the sensitivity of the circuit increases, since the current of one rectifying bridge (source) 3- keeps the diodes of the second rectifying bridge (gtochnik) -4 in the unlocked state, and vice versa m from both rectifying bridges (the sources flow in one direction (according to)) Simultaneously the constant voltage taken from the rectifying bridge 3, applied to diode 7, summing up the reististor 11 and the transistor Yu, keeps the latter in the locked state, and the constant voltage The voltage removed from the rectifying bridge 4, applied to the diode 8, the summing resistor 11 and the transistor 9, keeps the latter in the locked state, since there is no potential difference between the control current circuit electrodes (base emitter). Consequently, direct current does not flow through the external circuit, there is no voltage drop across the summing resistor, i.e. no output signal When the voltage on the secondary winding of the matching transformer 1 changes, for example, an increase, the DC voltage on the rectifier bridge 3 increases, which leads to a change in the magnitude of the difference of the potential® on the electrodes of the control circuit of the transistor U (on the base and on the collector) relative to the emitter), which opens and in the forward direction flows the current L from the positive potential of the rectifying bridge 3 through the diode 7, the summing resistor 11 and the transition of the transistor 10 to the negative the potential of the rectifier bridge 3, closing to the secondary winding of the matching transformer 1 The device operates similarly when the voltage on the secondary winding of the matching transformer 2 (equivalent to decreasing the voltage on the secondary winding of the matching transformer l) increases, the difference is in this case, the transistor 9 opens and the current 3 / flows through the circuit from the positive potential of the rectifying bridge 4, through (Cmsc 8 and the summing resistor 11 in the forward direction through the transition of the transistor 9 on -negative potential bridge rectifying unit 4, the closure Referring to the secondary winding of the matching transformer 2. Consequently, if the voltage prevails in the secondary winding of any transformer, the polarity of the DC voltage on the summing resistor changes, which is proportional to the prevalence of voltage on one secondary winding of the transformer relative to the second other transformer. In the proposed scheme, an increase in the transmission coefficient is achieved as a result of the current flowing through the summing resistor (external circuit) closing from the positive potential directly to the negative of the corresponding rectifying bridge, besides the elements of the internal circuit of resistors 5 and 6, Formula of the invention containing two matching transformers, the secondary windings of which are connected to the diagonals of two rectifying bridges, the colors of the coupling resistor included: between different Direct outputs of rectifying bridges, and a summing resistor, characterized in that, in order to increase the transmission coefficient, the transistor and two diodes are inserted in it, with one output of each of the communication resistors connected to the collector of the transistor , the emitter of the transistor through the diots is connected to its base and directly to the output of the summing resistor. Sources of information taken into account in the examination: 1 USSR author's certificate NO 439764, cl. Q 01 R 19/10, 1974. ri.