DE1591997C - RMS rectifier - Google Patents

Description

Then the load resistances have to be expanded differently 300: 1 if ^ ₁ = 0.01 is chosen

can be chosen, and their currents are to be added. will.

In this case, the load resistance of the In F i g. 3 is a practical embodiment of the rectifier G ₁ q times as large as that of the rectifier G _{2 of} a rectifier circuit according to the invention. The internal resistance of the equals shows. The rectifier G ₂ here consists of the rectifier G ₂ is then only k.JiqkJ times the two diodes D ₃ and D ₄ , which are connected via a load to those of the rectifier G ₁ . resistance R _{5 connected} to the measuring voltage U · The optimal dimensioning rule according to FIG. 2 and which also interact with charging capacitors C ₃ depends on the ratio of the duty cycle or C ₄ . These diodes are above the permissible measurement error range. This ratio io the resistances R ₃ and A _4, respectively, with an indicator is about 2500 for pulsed sinusoidal voltages instrument I in conjunction. The rectifier G ₁ or 10,000 for asymmetrical square-wave voltages in this circuit is provided by the rectifier D ₁ , the duty cycle range being around 0.8 / A ₁ and Z)., And the associated charging capacitors C ₁ or 3 / Ar ₁ amounts to. That means, for example, for and C, formed. These diodes D ₁ and D ₂ are square-wave voltages, as they apply as standard test signals 15 via the resistors R ₁ and R ₂ also with the fact that a rectifier combination with a display instrument I in connection. Under the A ₁ of 0.03 over a duty cycle range of assumption R ₁ = R ₂ and R ₃ = R _A and a negligible 100: 1 about ± 1% display error compared to the admissible small internal resistance of the display value with a duty cycle of 1: 1 has; If, for example, Instrument I can result in the following dimensioning 3% error, then the duty cycle can be set to 20 Regulation for this circuit:

_ Forward resistance value of diode D ₁ + volume resistance value of diode D.,

¹ ^ "■

, _ Forward resistance value of diode D ₂ + forward resistance value of diode D ₄ + 2A _n

^R 3

_{? =} A = A

From this circuit it becomes clear that the factor Ic _{1 of} the rectifier G ₁ cannot be chosen to be arbitrarily small in practice, but is limited by the finite resistance value of the rectifier used. In practice, however, values of ^ ₁ in the order of magnitude of 0.01 can easily be achieved.

1 sheet of drawings

Claims (2)

1 2 large change range of the duty cycle of the claims: measuring voltage to be rectified, for example in a change range of the duty cycle between 1. Rectifier circuit, the output of which see 1: 1 and 1: 100, with sufficient DC voltage An effective value measurement is permitted regardless of the curve shape. The applied alternating voltage to the effective This task is based on an equivalence of this alternating voltage, proportional, Richterschallung of the type mentioned inventively consisting of two such interconnected accordingly achieved in that the ratio of rectifiers with each associated charging between the charging and discharging resistance of the capacitors that the output currents io of the first rectifier are less than 0.1, preferably of these two rectifiers in a ratio of ad- charging resistance of the second rectifier determined by the 0.01 and the ratio between the charge and discharge duty cycle range, characterized in that up to a hundred times greater than this ratio of the ratio (kl) between the charging and first rectifier is chosen. Preferably the discharge resistance of the first rectifier (Gl) 15 is the second rectifier with a value of less than 0.1, preferably 0.01, and five to ten times greater value of the measurement voltage ratio (k 2) between the charge and discharge resistors - acted upon as the first rectifier, the second rectifier (G2) was thirty- By the inventive dimensioning of the rectifier circuits up to a hundred times greater than this ratio (A1), it is possible, for example, the first rectifier (Gl) is selected. 20 for square-wave voltages in one duty cycle 2. Rectifier circuit according to claim 1, range from 1: 1 to 1: 100 in the measurement error characterized in that the second equal- to keep the order of magnitude of 1% and at one richter (G 2) with a five to ten times duty cycle of 1: 300 still below the measurement error higher value of the measuring voltage applied to hold 3%. A measurement error of 10%, the is like the first rectifier (Eq.). 25 known rectifier circuits already at relatively low duty cycle occurs, the circuit according to the invention is only activated when a duty cycle occurs. ratio of 1: 1000 achieved. The rectifier circuit according to the invention is also in 30 Structure very simple. It can also be very simple The invention relates to a rectifier circuit implemented as a full-wave rectifier circuit whose output DC voltage is independent. Depending on the size of the gig of the waveform of the applied alternating duty cycle range to be covered, the rms value of this alternating voltage can be selected by the appropriate voltage The invention is explained in the following on the basis of schematic currents of these two rectifiers in a ratio determined by table drawings of exemplary embodiments in more detail, the duty cycle range,
add. '40 Fig. 1 shows on the basis of a block diagram the " It is from "Operating and Service Manual", 1967, the basic structure of an equation according to the invention Model 3555 A from the Hewlett-Packard Company, Richterschaltung; Loveland, USA., A rectifier circuit of this Fig. 2 shows on the basis of a diagram the supply Kind of known in which a so-called peak value relationship between the dimensioning pre-rectifier with a so-called mean value equation for the two connected rectifier is interconnected in such a way that the rectifier and its voltage control output currents add these two rectifiers. ratio; A peak value rectifier, which is therefore one of the F i g. 3 shows a transformerless embodiment Peak value of an alternating voltage proportional example. To supply DC output voltage, the basic 50 The rectifier circuit according to FIG. 1 also includes, if possible, designed without a series resistor, two in series with respect to the load resistance R _L , ie the ratio between charging and discharging rectifiers G ₁ and G ₂ . Resistance should be as close as possible to zero. Only the rectifier G ₁ is supplied with the measurement voltage U then you can be acted upon by a peak value rectifier, while the rectifier G ₂ one to speak. A mean value rectifier should, if possible, be supplied with a voltage qU which is greater than the factor q , not have a charging capacitor so that it also F i g. 2 shows in the curves I (for pulsed actually one of the mean value of the applied sinusoidal voltages) and II (for asymmetrical right AC voltage proportional output DC voltage corner voltages) delivers the optimal ratio IcJk _{1 of} the voltage. In the case of the known DC internal resistances of the two rectifiers "in the case of a rectifier circuit, this requirement is met by a common external resistance, and in the curve mean value rectifier, despite the III (sine) and IV (square) provided here, the optimal capacitors are met by a negative feedback. Ratio q between the rectifier G, (k.,) Such a known rectifier circuit and the one offered to rectifier G ₁ (&,) does not yet allow an ideal rms value display for AC voltage, provided that both rectifiers do not feed a common load resistance over a wide range of the duty cycle, namely the applied AC voltage. In the case of a transformerless version of the It is an object of the invention, an effective value rectifier circuit, it is useful both Rectifier halls to create that in one