JPH02184770A - Measuring instrument - Google Patents

Abstract

PURPOSE:To measure easily and simultaneously the output voltage and output resistance of an optional circuit network including an electromotive force by providing a 1st, 2nd capacitors and a load resistor. CONSTITUTION:When a 1st switching contact 3a is put ON, an open voltage of the circuit network 1 is charged to the 1st capacitor 4 and this charged voltage is displayed 9 as the output voltage of the circuit network 1. When a 2nd switching contact 5a is put ON at the time the contact 3a is in the OFF state, the electromotive force of the circuit network 1 is supplied to the load resistor 6 and a voltage generated on both ends of this resistor 6 is fetched to arithmetic means together with the output voltage. The calculation is made therein for the output resistance corresponding to an inside resistance, and the output resulted from this calculation is charged to the 2nd capacitor 13 at the time the 3rd switching contact is in the ON state, then this voltage is displayed 15 as the inside resistance of the circuit network 1. The output voltage and the inside resistance for the circuit network 1 can be simultaneously measured accordingly.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a measuring device for measuring the output voltage and output resistance (internal resistance) of any circuit network including an electromotive force.

(Prior Art) If a voltmeter is connected to the output terminal of any circuit network including an electromotive force, such as a power supply circuit consisting of a battery or the like, the output voltage of the power supply circuit can be determined.

On the other hand, since internal resistance exists in power supply circuits such as batteries, the output voltage will be lower than the actual electromotive force of the power supply circuit by the voltage drop caused by the internal resistance.

Therefore, in order to configure the power supply circuit so that the output voltage required by the load can be stably obtained, it is necessary to know the internal resistance (output resistance) of the power supply circuit.

Conventionally, as a means of determining the internal resistance of such a power supply circuit, the open circuit voltage of the power supply circuit and the voltage between the terminals when a known resistance is connected to the terminals are determined using a measuring instrument, and then these are measured. The internal resistance (output resistance) was calculated from the value using Thevenin's theorem.

(Problem to be solved by the invention) The conventional method of calculating internal resistance as described above requires a calculator such as a calculator in addition to a measuring instrument such as a voltmeter, and the procedure for calculating internal resistance is complicated. This would be time-consuming and extremely unrealistic.
Therefore, in the past, in most cases, only the output voltage was measured and it was determined whether this output voltage was within the desired range, and the internal resistance was almost ignored. was the current situation.

The present invention was made in view of the above points, and an object of the present invention is to obtain a measuring device that can simultaneously and easily measure the output voltage and output resistance (internal resistance) of any circuit network including electromotive force. .

(Means for Solving the Problems) In order to achieve the above object, the measuring device of the present invention has a first switching contact that is turned on and off at a predetermined cycle to measure the open circuit voltage of an arbitrary circuit including an electromotive force. a first capacitor to be charged via the first capacitor, an indicator for displaying the voltage charged in the first capacitor as the output voltage of the circuit network, and an output terminal of the circuit network opposite to the first switching contact; a load resistor connected via a second switching contact that turns on and off;
calculation means for calculating an output corresponding to the internal resistance of the circuit network based on the output voltage charged in the capacitor and the voltage across the load resistor, and synchronizing the output from the calculation means with the second switching contact. a second capacitor that is charged via a third switching contact that is turned on and off; and an indicator that displays the voltage charged in the second capacitor as an internal resistance of the circuit network. It is.

(Function) When the first switching contact is turned on, the first capacitor is charged with the open circuit voltage E of the circuit network, and this charging voltage is displayed as the output voltage of the circuit network by the display.

On the other hand, when the second switching contact is turned on while the first switching contact is off, the electromotive force of one circuit network is supplied to the load resistor, and the voltage V generated across the load resistor is calculated by the calculation means as well as the output voltage. Here, the output resistance corresponding to the internal resistance is calculated based on Thevenin's theorem, and the output that is the calculation result is charged to the second capacitor when the third switching contact is turned on, and this charging voltage is displayed. is displayed as the internal resistance of the network.

Therefore, with the present invention, the output voltage and internal resistance of the network can be measured simultaneously.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 is an overall configuration diagram showing an embodiment of a measuring device according to the present invention.

In the figure, l is an arbitrary circuit network including an electromotive force, consisting of a DC power source 2 such as a battery, and equipped with an internal resistance r.

Output terminal T1 . of said network l. T, has the first relay 3
A first capacitor 4 is connected in parallel, which charges the open circuit voltage E of the network l via the normally open contact 3a of the output terminal T1. A normally open contact 5 of the second relay 5 is connected between T and a.
A load resistor 6 (resistance value R) is connected in parallel via a.

The subtraction circuit 7 has a normally open contact 3a and a capacitor 4.
The connection point PI with the normally open contact 5a and the connection point P2 with the load resistor 6 are connected, respectively, so that the subtraction circuit 7 receives the output voltage E charged in the capacitor 4 and the load resistance 6.
The voltage ■ generated across the terminal is supplied. Further, a display 9 such as a voltmeter that displays the output voltage E is connected to both ends of the first capacitor 4 via a buffer 8.

The division circuit 10 receives the voltage E- output from the subtraction circuit 7.
It calculates the ratio between V and the voltage V generated across the load resistor 6, and the output side has a gain G corresponding to the load resistor H.
A third relay 12 is connected between the output terminal of the amplifier 11 and the (-) terminal 18 of the circuit network l.
The output voltage R from the amplifier 11 via the normally open contact 12a of
A second capacitor 13 for charging (E-v) is connected, and both ends of the second capacitor 13 are connected via a buffer 14 to correspond to the internal resistor r.

The second relay 5 and the third relay 12 are directly supplied with a clock signal CLK of a predetermined frequency f, and the second relay 3 is supplied with the clock signal CLK by an inverter 16.
An inverted clock signal is supplied.

Next, the operation of simultaneously measuring the output voltage and internal resistance of the circuit network I by the measuring device of this embodiment configured as described above will be explained with reference to the time chart of FIG.

When the clock signal CLK having the waveform shown in FIG. 2(a) is applied to the clock input terminal 17, the signal (see FIG. 2) which is inverted by the inverter 16 when the signal is "L" is applied to the first relay 3. Therefore, the first relay 3 is energized and its normally open contact 3a is closed. Along with this, the circuit network l
from the DC power supply 2 through the internal resistance r and the contact 3a.
A current flows through the capacitor 4, and the capacitor 4 is charged to the output voltage E of the network I as shown in FIG. 2(C).

This charging voltage E is taken into the subtraction circuit 7, and
It is applied to a display 9 via a buffer 8, so that the display 9 displays the output voltage E of the network I.

On the other hand, when the clock signal CLK applied to the input terminal 17 changes to "H", the first relay 3 is deenergized, the second relay 5 and the third relay 12 are energized, and the normally open contacts 5a, 12a is closed. By closing the normally open contact 5a, the output voltage E of the circuit network 1 is applied to the load resistor 6, and the voltage V across the load resistor 6 generated at the connection point P2 is supplied to the subtraction circuit 7 and the division circuit 10. be done. Accordingly, the subtraction circuit 7 calculates E-v, and the division circuit IO calculates the calculation result E-v output from the subtraction circuit 7.
The signal that performs the 1-1-1 calculation based on the voltage V appearing at the connection point P2 by the load resistor 6 is amplified by the amplifier 11, and its amplified output R(E-
v)- is charged to the second capacitor 13 through the closed normally open contact 12. At this time, the charging voltage of the capacitor 13 becomes vr (see Figure 2 d).
, this voltage vr is applied to the display 15 via the buffer 14, thereby causing the display 15 to have an internal resistance r of the network 1.
Display.

That is, the output voltage E obtained by closing contact 3
Based on the voltage V across the load resistor 6 obtained by closing the contact 5a, the subtraction circuit 7, the division circuit 1O, and the amplifier 11 perform the calculation of r=R- obtained from Thevenin's -v theorem. As a result, when the voltage vr charged in the second capacitor 13 is applied to the display 15, the display 15 measures the internal resistance r of the circuit network l.

As described above, in this embodiment, the measurement device having the circuit configuration shown in FIG. 1 is connected to the output terminals T, T2 of one circuit 1ull, and the circuit The output voltage E and internal resistance r of the network I can be measured almost simultaneously, and the measurement operation is also simple, making it possible to perform accurate measurements without individual differences.

In the above embodiment, the output voltage display and internal resistance (
Although we have shown the case where a meter-type display is used to display (output resistance), it is not limited to this, and a digital display method may also be used. In this case, the analog output from each buffer is converted to a digital quantity and a digital display is used. You can output it to .

Further, the circuit means for calculating internal resistance based on Thevenin's theorem in the present invention includes a subtraction circuit 7, a division circuit IO
and is not limited to the amplifier 11.

(Effects of the Invention) As described above, according to the present invention, the output voltage and output resistance of any circuit network including electromotive force can be easily measured simultaneously and without any complicated steps.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram showing an example of a measuring device according to the present invention, and FIG. 2 is a time chart for explaining its operation. In the figure, 1 is a circuit network, 3 is a first relay, 3a is a normally open contact, 4 is a first capacitor, 5 is a second relay, 5a is a normally open contact, 6 is a load resistance, 7 is a subtraction circuit, 9 is an output voltage display, and lO is a divider circuit. 11 is an amplifier, 12 is a second relay, 13 is a second capacitor, and 15 is an internal resistance indicator.

Claims (1)

[Scope of Claims] A first capacitor that charges an open-circuit voltage of an arbitrary circuit including an electromotive force through a first switching contact that is turned on and off at a predetermined cycle; and a first capacitor that charges the first capacitor. a load resistor connected to the output end of the circuit network via a second switching contact that turns on and off in the opposite manner to the first switching contact; and a calculation means for calculating an output corresponding to the internal resistance of the circuit network based on the output voltage charged in the first capacitor and the voltage across the load resistor; A second battery that charges via a third switching contact that turns on and off in synchronization with the switching contact of the
A measuring device comprising: a capacitor; and an indicator that displays the voltage charged in the second capacitor as an internal resistance of the circuit network.