SU1430764A1 - Device for measuring coefficient of luminescence pulsations - Google Patents

Abstract

The invention relates to measuring instruments, in particular, used for the determination. light ripple factor. The goal is to reduce material intensively. these devices and the possibility of direct reading of measurement results. The device is equipped with a measuring bridge, two differential amplifiers, two non-inverting amplifiers, an alternating current amplifier, amplitude-detectors of max-1 minimum and minimum signals, an operation mode switch. First, the measuring bridge is balanced, then the voltage is set to correspond to a fixed average value of illumination. In the third position of the operation switch 1-5 1a on the scale of the measuring instrument, the value of the pulsation coefficient of the light is measured. 3 il.

Description

Willow

f

O5

The invention relates to measuring instruments, in particular j, used to determine the pulsation coefficient of the illuminance.

The purpose of the invention is to reduce the material consumption of the device and to provide the ability to directly read the measurement results to determine the ripple rate of seediness.

Fig. 1 shows the electrical circuit of the device in principle; in fig. 2 - npi-iMep power supply circuit design | in FIG. 3 a temporal diagram of the pulsation is illuminated -. ty ;, napkkerker, from the incandescent lamp

The device contains a primary converter 1z made, for example, j on a photodiode, included in one of the player's measuring bridge O.j 2.j which contains a variable resistor 3c The outputs of the measuring bridge 2 are connected to the inputs of the first differential amplifier 4s whose outputs are connected to the input of the first non-inverting amplifier 5 and the first input of the operation mode switch 6 The non-inverting amplifier 5 contains a variable resistor 7 "The output of the non-quantizing amplifier 5 is connected to the input of the amplifier 8 AC, and the second inputs of the 6-mode switch The output of the AC amplifier 8 is connected to the input of the amplitude detector 9 of the minimum signal and the input of the amplitude detector 10 of the maximum signal, the output of the amplitude detector 9 of the minimum signal is connected to the inverter O; and the output of the amplitude detector 10 of the maximum signal is with the non-inverting input of the second differential amplifier 1I. The output of the differential amplifier 1I is connected to the input of the second non-instructor amplifier 12; the output of which is connected to the third input of the parakeeper 6 mode of operation. The non-inverting amplifier 12 contains a trimming resistor 13. The measuring device 14 is connected between the output of the operating mode switch b and the common drive of the power supply 15.

Calculation of the pulsation coefficient of illumination K | produced according to the formula

. E max - Ew.ui-i. „„

Kp -. ---- .- 1ii „

l, r

where K „

light ripple factor

 M "KS

min

and E

wed

respectively, maximum, minimum and average values of illumination at the point of measurement (Fig. 3), lx.

If the value of Ecp is reduced to some fixed reference value A, for example 2 lk, then the formula for Kp is an example view;

K 5 () .JQQ ME.JQQ

2 tons - - 100 25 tlE,

2A

0

five

0

0

five

five

.- E „

0 where m is the scale factor

a decrease (increase) in the mean luminance value at the measurement point; - the amplitude value of the pulsation of illumination at the measuring point, lx,

The device works as follows.

The switch 6 of the operating mode is set to the first position. The primary converter 1 is darkened and the variable resistor 3 according to the measuring device 14 sets a zero voltage at the output of the differential amplifier 4. In this way, a detuning from the dark current of the primary converter, which depends on the temperature, is made. Next, set the operation mode switch 6 to the second position, and the primary transducer is placed at the point where it is necessary to measure the pulsation coefficient of the illuminance. In this case, the conductivity of the primary converter 1 varies depending on the illumination. This leads to imbalance of the measuring bridge 2. The unbalance signal is fed to the input of the differential amplifier 4 and then to the input of the non-inverting amplifier 5. The variable resistor 7 on the measuring device 14 sets the output voltage of the non-inverting amplifier 5 corresponding to a fixed average illumination value regardless converter Next, re-.

the switch 6 of the operating mode is set to the third position. The output signal of the non-inverting amplifier 5 is fed to the input of the amplifier 8 AC. At the output of the amplifier 8, there is a signal of only a variable component of the luminance pulsation. The signal corresponding to the minimum level of the variable component is extracted by the amplitude detector 9 of the minimum signal, and the signal corresponding to the maximum level of the variable component is output by the amplitude detector IO of the maximum signal. From the output of the amplitude detectors 9 and 10, the signals arrive at the inputs of the differential amplifier 11, where they are summed up. The sum signal corresponding to the amplitude value of the variable component E (FIG. 3) is fed to the input of the non-inverting amplifier 12. Amplifier 12 amplifies the input signal with a constant coefficient (25) which is set by the trimming resistor 13 when the device is tuned. The ripple factor is measured on the scale of the measuring device 14,

Claims (1)

Invention Formula A device for measuring the pulsation coefficient of the illumination, comprising a primary transducer, a power source, a measuring instrument, characterized in that. 0 five five that, in order to reduce material consumption and enable direct measurement of measurement results, the device is equipped with a measuring bridge, two differential amplifiers, two non-inverting amplifiers, an alternating current amplifier, amplitude detectors of maximum and minimum signals, an operation mode switch, the primary converter is included in one of the arms of the measuring bridge, the outputs of which are connected to the inputs of the first differential amplifier, the output of which is connected It is connected to the first input of the operating mode switch and to the input of the first non-inverting amplifier, the output of which is connected to the second input of the operating mode switch and the input of the AC amplifier, the output of which is connected to the inputs of amplitude detectors of the maximum and minimum signals, is connected to the non-inverting the input of the second differential amplifier, the inverting input of which is connected to the output of the amplitude detector of the minimum signal, the output of the second differential entsialnogo uchilitel through the second non-inverting amplifier co unified with the third input of the switch operation, and the measurement - the device is connected between the output of the switch mode power supply and obschim.provodom. 0 0 s / zig-2