SU1492322A1 - Device for electric testing of amplifiers of sound reproduction equipment - Google Patents

Abstract

The invention relates to the field of instrumentation and can be used to control the reliability of amplifiers of audio-reproducing equipment. The purpose of the invention is to expand the field of use of the device by using a controlled equivalent load and simplifying the device. To achieve the goal, a control unit 10, a transformer 7, switches 9.1 ... 9.N, input terminals 8.1, 8.2 are inserted into the device for connecting a stimulating generator. The device also contains an excitation generator 5, input clips 1.1 ... 1.N, 2.1 ... 2.N, output clips 3.1 ... 3.N, 4.1 ... 4.N of the control object, two-terminal 6.1 ... 6.N load. 1 il.

Description

The invention relates to instrumentation engineering, in particular, for testing electronic amplifiers of sound-reproducing equipment for reliability and an electric drive train.

The purpose of the invention is to improve the scope of use by using a controlled load equivalent and simplifying by eliminating chokes and non-polar capacitors.

The drawing shows a diagram of the proposed device.

The device for electrodiagnostic amplifiers contains input terminals

1.1, 1.21.P and 2.1, 2.2, ... 2.P

control object, output clamps 3.1, 3.2, ..., 3.p. and 4.1,4 .2 ... A.n. control object, excitation generator 5, two-terminal 6,1,6.2, ... 6.P load, transformer 7, input terminals 8.1 and 8.2 for connecting a stimulating generator, breakers (switches) 9.1, 9.2, ..., 9.n., control unit 10, the excitation generator 5 connected to the corresponding input terminals 1 .1,1.2, ...,. P and 2.1, 2.2, ..., 2.p of the control object, the output terminal 3.1 of the control object is connected to the first output of the two-terminal 6.1 load, the second output of which is connected to the second output through the interrupter 9.1 The secondary winding of the transformer 7, the first output of which is connected to the output terminals 4.1, 4.2, ..., 4.p of the test object, the control input of the chopper 9.1 is connected to the corresponding output of the control unit 10 the primary winding of the transformer 7 is connected to the input 8.1 and 8.2 terminals for connecting the stimulating generator.

The device works as follows.

Voltage supplied to the input terminals 1., ..., p and 2.1, ..., 2.p of the test object from the excitation generator 5 and from the stimulating generator (AC network) to the input terminals 8.1 and 8.2 for connecting the stimulating generator lead to the formation of electrical voltages on electrical elements and the output of the voltage, which are similar to those obtained with an electric drive with a load on the loudspeaker or its equivalent. The value of the current flowing through

ten

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thirty

492322

The two-port 6.1 can be set equal to the value of the current flowing through the loudspeaker equivalent by selecting the values of the alternating voltages at the two ends of the two-terminal 6.1 — one at the output of the equipment, the second at the output of the transformer 7.

Since the frequencies of these voltages are different (the first voltage is a signal from a source of musical programs or a sinusoidal signal with a dominant frequency of 500-2000 Hz, and the second voltage is a frequency of 50 Hz) and due to the absence of correlation between these voltages, the instantaneous values of the current in the electric elements of the amplifier, as in the case of using the loudspeaker of Š1I ei o equivalent, are in arbitrary phase relations with the values of the voltages on these elements. A number of amplifier elements, for example, output transistors, may have a working point trajectory with entry into unacceptable specifications on the transistors of the mode region, which is observed when the amplifier is operated on a real loudspeaker or its equivalent. The electrical equivalent of a loudspeaker is a parallel resonant circuit tuned to a frequency of 50 Hz, which in the process of electrodynamic equipment accumulates a portion of the signal energy produced in the load in the vicinity of the resonance frequency and then returns it to the output amplifier circuit as a variable uncorrelated with the generator signal 5 is the excitation component of the current with a frequency of 50 Hz.

The switches 9.1, controlled from the control unit 10, allow the ratios between the peak and average power dissipated at the collector of the amplifier transistor to vary, since the peak factor of different types of music programs is different.

In order to improve the measurement accuracy of 50% amplifiers of sound reproduction, it is advisable to connect the equipment to the inverting and non-inverting outputs of the excitation generator 5, which eliminates the error that occurs during the formation of the boundaries of the mode region of the output stage transistors, which occurs due to ToK in general for

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all two-terminal load of resistance of the transformer windings.

Claims (1)

Invention Formula A device for electrodynamic amplifiers of sound-reproducing equipment, containing a wiper generator, connected in parallel to the input terminals of the test object, and two-terminal loads, the first terminals of which are connected respectively to the first output terminals of the test object, in order to expand the scope and simpler input terminals for connecting a stimulating generator, a control unit, a transformer, switches, the first output of the secondary winding of the transformer is connected to the second output terminals of the test object, the second output is connected to the corresponding output breaker through the corresponding breaker, the control inputs of the choppers are connected the control unit outputs; the primary winding of the transformer is connected to the input terminals for connecting a stimulating generator.