RU221233U1 - PULSE DURATION METER - Google Patents

Abstract

The utility model relates to measuring technology, namely to measuring the duration of short electrical voltage pulses following at intervals whose duration is significantly longer than the duration of the pulses themselves. The technical result achieved by the solution is to simplify the determination of the duration of a series of pulses. The specified technical result is achieved due to the fact that a pulse duration meter has been developed, containing a housing with inputs for connecting a pulse source, a voltmeter with a digital display, configured to display the voltage on the capacitor, characterized in that the housing contains an electronic circuit that includes an integrating circuit from a resistor and a capacitor, configured to be charged upon receipt of pulses from the pulse source, a reset pulse delay driver electrically connected to the reset pulse driver, configured to, upon receipt of pulses from the pulse source, trigger the reset pulse driver after a predetermined time less than the duration of time between the pulses of the pulse source, a reset pulse driver electrically connected to the relay, configured to direct the reset pulse to the relay, the relay configured to discharge the integrating circuit upon receipt of the reset pulse.

Description

Field of technology to which the utility model relates

The utility model relates to measuring technology, namely to measuring the duration of short (about 100 μs) electrical voltage pulses following at intervals whose duration (about 1 s) is significantly longer than the duration of the pulses themselves.

The utility model is primarily intended for measuring the duration of voltage pulses arising during laboratory work devoted to the study of the process of collision of elastic metal balls suspended on electrically conductive suspensions connected to an electrical circuit.

State of the art

There are industrial digital devices specifically designed for measuring the duration of electrical pulses when performing laboratory work and having appropriate sockets for connecting to an experimental setup (see, for example, https://www.uchebnayatekhnika.rf/wps/cifrovoj-izmeritel-vremennyx-intervalov -fm-11-1/).

The main disadvantage of specialized industrial devices is their high complexity and cost. Other disadvantages of the known devices are limited functionality and unsatisfactory ergonomic characteristics.

Using such instruments, it is possible to measure the duration of only one pulse (that is, the duration of only one collision of balls). To repeat the measurement, you must click on the “Reset” button located on the front panel of the device, but before that you must write down the result of the previous measurement in your laboratory notebook.

The interval between repeated collisions is equal to half the period of oscillation of the balls, which depends on the length of the suspension. The suspension length is usually 0.5 - 0.8 m, with the oscillation period varying between 1.4 - 1.8 s. In 0.7 - 0.9 s you can have time to record the measurement result, but it is impossible to perform several different types of actions with objects located in different zones of attention (reading the measurement result from a digital display, writing the result in a notebook, pressing a button on the instrument panel). The situation is not helped by the currently widely used method of recording instrument readings - video recording on a smartphone camera, since simultaneous video recording and periodically pressing the “Reset” button is very difficult.

The device chosen as a prototype is known (Mechanics and thermodynamics: methodological instructions for the introductory lesson and laboratory work No. 0-6 in physics / Novosibirsk State Technical University; [compiled by: A.V. Baranov and others] - Novosibirsk: NSTU Publishing House, 2004. - 69 pp. URL: http://elibrary.nstu.ru/source?bib_id=vt1s000042968) to measure the duration of pulses arising from the collision of balls, based on the process of discharging a pre-charged capacitor and including a voltage source with a power switch, a switch, a capacitor with a known electrical capacity C, a resistor with a known resistance R and a digital voltmeter with a high input impedance that records the voltage across the capacitor. In the initial state, the capacitor is charged to the source voltage U0. Before starting measurements using a switch, the capacitor is disconnected from the source. When the balls collide, the electrical circuit is closed, the capacitor begins to discharge through the resistor and the voltage on the capacitor decreases to the value U. After the end of the pulse, this voltage remains unchanged for some time (the discharge of the capacitor through a voltmeter with high resistance occurs quite slowly) and is displayed on the digital indicator of the voltmeter . Using the values of U0, U, R and C, the pulse duration is calculated.

The advantages of a device built on the basis of the capacitor discharge process as an educational device are low cost, simplicity of design, a principle of operation that is understandable to students, as well as the ability to illustrate a new indirect method for measuring time for students by converting a time interval into voltage, which broadens the horizons of students and their an idea of the possibilities of using a device familiar to them - a capacitor, which contributes to the accumulation of the heuristic potential of students' thinking.

Using this device, it remains impossible to measure the duration of pulses that follow each other during repeated collisions of the balls, since before each measurement it is necessary to perform several actions (read from the digital display of the voltmeter and write down the result of the previous measurement in a notebook and then, changing the position of the switch, connect capacitor to the source and turn it off again.The duration of all these different types of actions with objects located in different zones of attention exceeds the duration of the interval between impulses.

The disadvantages of this device also include the inverse relationship between the pulse duration and the readings of the digital voltmeter (as the capacitor discharge time increases, the voltage across it decreases), which requires additional explanation and leads to the need to calculate the pulse duration using the formula.

Disclosure of utility model

In one aspect of the utility model, a pulse duration meter is disclosed, comprising:

- housing with inputs for connecting a pulse source;

- a voltmeter with a digital display, capable of displaying the voltage on the capacitor,

characterized in that

the housing contains an electronic circuit including

- an integrating circuit of a resistor and a capacitor, designed to be charged when pulses are received from a pulse source,

- a reset pulse delay driver, electrically connected to the reset pulse driver, configured to, upon receipt of pulses from the pulse source, start the reset pulse driver after a predetermined time less than the duration of time between pulses of the pulse source,

- a reset pulse driver electrically connected to the relay, configured to direct the reset pulse to the relay,

- a relay configured to discharge the integrating circuit upon receiving a reset pulse.

In additional aspects, it is disclosed that the source of the pulses is colliding metal balls on electrically conductive suspensions; contains a switch for measuring a single pulse and a sequence of pulses; It is possible to display on the voltmeter numerical values corresponding to the time of impact of the balls in a given range of pulse durations.

The main objective of the claimed solution is to create a simple and easy-to-use device for measuring the parameters (duration) of individual pulses in a series of pulses.

The technical result achieved by the solution is to simplify the determination of the duration of individual pulses in a series of pulses.

The specified technical result is achieved by the fact that the device containing a voltage source with a power switch, a capacitor, a resistor, a digital voltmeter with a high input resistance and contact sockets for connecting to an experimental setup, also contains a reset pulse delay driver, a reset pulse driver, a relay with one switching contact group, operating mode switch for two positions, push-button switch for two positions without fixing, while the resistor and capacitor are connected according to an integrating circuit circuit, the output of which is connected to the input of a digital voltmeter, the input of the integrating circuit is connected to the input of the reset pulse delay driver, the output of the driver the reset pulse delay is connected to the input of the reset pulse shaper, a relay winding is connected to the output of the reset pulse shaper, the input of the integrating circuit is also connected to the common contact of the operating mode switch for two positions, in the first of these positions the input of the integrating circuit is connected to the common contact of the push-button switch for two position without fixation, in the second position - to the common contact of the relay contact group, the normally closed contact of the push-button switch is connected to the normally open contact of the relay and to the common wire, the normally open contact of the push-button switch is connected to the normally closed contact of the relay and to one of the three input contact sockets meter, while the other two input contact sockets are connected respectively to the output of the voltage source and to a common wire, all of the listed elements are fixed inside a flat housing, while the front panel is the upper horizontal surface of the housing, on which a non-latching push-button switch is located on the left, and on the right - The digital display of the voltmeter, other controls (power switch, operating mode switch), as well as input contact sockets are located on the side surfaces of the case. Brief description of drawings

In fig. Figure 1 shows a block diagram of a pulse duration meter.

Fig. 2 shows the dependence of the voltmeter readings on the pulse duration.

Implementation of a utility model

The proposed device is shown in figure 1, in which

XS1, XS2, XS3 - input contact sockets;

K1 - operating mode switch with two positions;

K2 - push-button switch with two positions without fixing;

K3 - relay contact group;

C - capacitor of the integrating circuit;

R - resistor of the integrating circuit;

1 - voltage source with power switch;

2 - digital voltmeter with high input resistance;

3 - reset pulse delay driver;

4 - reset pulse former;

5 - relay winding.

All elements of the claimed solution are connected to each other through assembly operations so as to ensure structural and functional unity. To connect the elements to each other, any operation that is obvious to a person skilled in the art can be performed: soldering, welding, threaded connection, connection using friction forces. Unless specifically stated, the specific type of connection is not essential to the stated solution.

In the initial state, shown in Figure 1, the input contacts XS1 and XS2 are open, capacitor C through resistor R and the normally closed contacts of switches K1 and K2 are connected to the common wire and discharged, voltmeter 2 connected to the capacitor shows zero

The device can operate in two modes - manual and automatic.

In manual mode (when switch K1 is in the upper position), immediately before closing contacts XS1 and XS2 (this moment is determined visually by the experimenter by observing the movement of colliding balls), press button K2 and connect input contact XS2 to the input of the integrating circuit (resistor R). When contacts XS1 and XS2 are closed, voltage U0 of source 1 is applied to the input of the integrating circuit, the capacitor begins to charge and, in a time equal to the pulse duration, is charged to voltage U.

As is known, the change in voltage U on capacitor C, connected to source 1 of constant voltage U0 through resistor R, changes according to the function U=U0(1 - exp(-t/RC)), which in the initial section (at t<<RC) almost linear. The values of C and R are chosen such that the value of U at t equal to the typical value of the pulse duration τ of about 100 μs is about 10% of U0, and the readings of voltmeter 2 (in tens of mV) are numerically equal to the pulse duration in microseconds.

After reading the readings of voltmeter 2, button K2 is released, while the input of the integrating circuit is connected to the common wire and the capacitor is discharged through resistor R.

In automatic mode (when switch K1 is in the lower position), voltage pulses through the normally closed contact of the contact group of relay K3 are supplied to the input of the integrating circuit with each collision. These pulses are simultaneously supplied to the input of the reset pulse delay driver 3, which after 0.5 s triggers the reset pulse driver 4, causing relay 5 to operate, connecting the input of the integrating circuit to the common wire for a time of 0.1 s, which leads to a rapid discharge of capacitor C and resetting the readings of voltmeter 2 to zero, so after 0.6 s the device is ready to measure the duration of the next pulse.

Thus, two operating modes of the device provide the ability to determine the duration of both single pulses and pulses following each other, while the duration of the pulses is determined directly from the readings of digital voltmeter 2, without additional calculations.

The presence of an automatic reset allows the experimenter to concentrate on the process of recording instrument readings - in a notebook or using a video recording. Manufacturing a pulse duration meter in a flat case with a digital display on the top horizontal front panel allows it to be placed next to a workbook or in an area convenient for video recording, which simplifies the measurement process.

The design of the utility model used voltage source 1 with output voltage U0=10 V, digital voltmeter 2 with input resistance 1 MOhm, relay 5 RES-15 RS4.591.002. The reset pulse delay driver 3 and the reset pulse driver 4 are made according to known circuits (see, for example, Horowitz P., Hill. U. The Art of Circuit Design: In 3 volumes: Vol. 2. Translated from English - 4th ed., revised and additional - M.: Mir, 1993. - 371 pp.). Parameters of the integrating circuit: C=47 μF and R=20 Ohm.

The operation of the device was studied by applying voltage pulses with an amplitude of 10 V with a given duration, which were generated by a pulse generator, the output of which was connected to sockets XS2 and XS3. With the selected parameters of the integrating circuit, the time constant for charging the capacitor is 940 μs and with a pulse duration of τ = 100 μs, the voltage displayed on the display of voltmeter 2 is U = 1.00 V. This number, if you do not take the comma into account, coincides with the pulse duration ( the comma on the digital display of voltmeter 2 is turned off, painted over or covered with an opaque mask).

Figure 2 shows the results of tests of the utility model in the form of a graph of the dependence of the readings of digital voltmeter 2 (in tens of millivolts) on the pulse duration (in microseconds).

As you can see, the experimental points are located next to the line corresponding to the exact equality: U=τ. In the interval from 0 to 200 μs, the relative error is up to 5%; in the interval of the most probable values of the pulse durations arising from the collision of the balls (from 50 μs to 150 μs), the relative error is up to 2.5%.

The embodiments are not limited to the embodiments described above, but other embodiments of the solution will become apparent to one skilled in the art based on the information set forth in the description and knowledge of the prior art, without departing from the spirit and scope of this solution.

Elements referred to in the singular do not exclude the plurality of elements unless specifically stated otherwise.

While exemplary embodiments have been described in detail and shown in the accompanying drawings, it is to be understood that such embodiments are illustrative only and are not intended to limit a broader solution and that the solution should not be limited to the specific arrangements and structures shown and described, since various other modifications may be apparent to those skilled in the art.

The features mentioned in the various dependent claims, as well as the implementations disclosed in various parts of the description, can be combined to achieve beneficial effects, even if the possibility of such combination is not explicitly disclosed.

Claims (12)

1. Pulse duration meter containing: - housing with inputs for connecting a pulse source; - a voltmeter with a digital display, capable of displaying the voltage on the capacitor, characterized in that the housing contains an electronic circuit including: - an integrating circuit of a resistor and a capacitor, designed to be charged when pulses are received from a pulse source, - a reset pulse delay driver electrically connected to the reset pulse driver, configured to trigger the reset pulse driver upon receipt of pulses from the pulse source after a predetermined time less than the duration of time between pulses of the pulse source, - a reset pulse driver electrically connected to the relay, configured to direct the reset pulse to the relay, - a relay configured to discharge the integrating circuit upon receiving a reset pulse. 2. The meter according to claim 1, in which the source of pulses is colliding metal balls on electrically conductive suspensions. 3. The meter according to claim 1, containing a switch for measuring a single pulse and a sequence of pulses. 4. The meter according to claim 2, configured to display on the voltmeter numerical values corresponding to the time of impact of the balls in a given range of pulse durations.