JPS60126916A - Positive and negative pulse generating circuit of electric detector - Google Patents

Abstract

PURPOSE:To prevent the occurrence of electrodialysis at an electrode when the resistance of an electrolyte is measured by composing a circuit of an oscillation circuit, two positive and negative power sources, and plural switching which are driven by the oscillation circuit and connected to the positive and negative power sources. CONSTITUTION:The switching means 4 and 5 use a PNP transistor (TR) at a positive power source side and an NPNTR at a negative power source side to obtain a pulse with a sharp waveform. Further, the connection point of resistors 6 and 7 and the middle point of the positive and negative power sources 9 and 10 are regarded as an output terminal 8. Then, Trs 4 and 5 are operated alternately through driving means 2 and 3 with a pulse train from the oscillation circuit 1. When the Tr4 is operated, a current flows from the positive power source 9 to the middle point of the power sources through a resistor 6, output terminal 8a, resistance (rx), and 8b. When the Tr4 is turned off and the Tr5 is operated, a current flows from the middle point of the power sources to the negative power source through the output terminal 8b, resistance (rx), 8a, and resistor 7. Therefore, the currents in both directions flow through the resistance (rx).

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an electrical detection device, and provides a simple generating circuit for positive and negative pulses for measuring ion concentration in an aqueous solution. This makes it possible to detect taste etc.

The structure of conventional examples and their problems In recent years, when cooking, etc., the weight of ingredients, heating time, etc. have been quantified, but taste has not yet been quantified, and it is difficult to enter it at the cash register. There is no particular mention of using concentration example 1. On the other hand, when quantified,
These measuring instruments, which did not exist before, will be needed.

For example, the concentration of common salt is ``karami'', but when trying to measure it in a general household, the simplest method is to measure it, for example, by electrical resistance. Not only salt, but also acids (sour taste), alkalis (concentration of soap liquid), etc. can be measured by electrical resistance.

When attempting to measure resistance by applying direct current to these electrolytes, electrolysis of water occurs and the resistance value near the electrodes changes, making stable measurements impossible.

On the other hand, when alternating current is applied, no electrolysis occurs and stable measurements can be made, but the circuit becomes complicated.

Purpose of the Invention The present invention aims to provide a positive and negative pulse generation circuit with a simple configuration that can prevent the occurrence of electrolysis at the electrodes when measuring the resistance of an electrolytic solution. Electrical detection devices such as liquid resistivity can be easily constructed.

Structure of the Invention In order to achieve this object, the positive and negative pulse generation circuit of the present invention uses one oscillation circuit, two positive and negative power supplies, and an oscillation circuit! 7
It consists of a switching means connected to a plurality of positive and negative power supplies to be driven, and the switching means are connected by a resistor, and the connection point and the midpoint of the two positive and negative power supplies are configured as an output terminal.

(The switching means is PNP on the positive power supply side)
DESCRIPTION OF THE EMBODIMENT An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the electrical configuration of a positive and negative pulse generation circuit according to an embodiment of the present invention.0 In FIG. 1, 1 is an oscillation circuit that generates pulses of a specific frequency. ．．
3 is a driving means for the switching means; 4 is a switching means connected to a positive power source which will be described later; and 5 is a switching means connected to a negative power source which will be described later. The switching means 4 and 5 are connected by a resistor 6.7, and this connection point and the midpoint between the positive and negative power supplies 9.10 are used as the output terminal 8.

FIG. 2 shows a specific circuit configuration of an embodiment of the present invention.

In Fig. 2, 11 and 12 are NPN transistors, which together with resistors and capacitors constitute an astable multivibrator circuit. 13 is an NPN transistor, exp.

The nential waveform is shaped into a square wave.

Reference numeral 14 denotes a PNP transistor, which together with the NPN transistor 15 constitutes a drive circuit for an NPN transistor 16 which constitutes a switching means connected to a negative power supply.

Q transistor 16 and transistor 17, which are PNP (PNP) transistors constituting switching means connected to a positive power supply, are connected by resistors 18 and 19, and external measured resistance 2° is the connection between resistors 18 and 19. It is connected between the positive power source 21 and the negative power source 22.

The operation of the pulse generation circuit configured as described above is as follows. First, in the block diagram of FIG. 1, the oscillation circuit 1 generates a pulse train of a preset frequency. This pulse train causes the switching means 4.5 to be operated alternately via the driving means 2.3. When the switching means 4 is operated, the positive power supply 9 is activated.
through resistor 6 - output terminal 8a → resistor rx → 8b
→A current is generated to the midpoint of the power supply.

Next, the switching means 4 is stopped, and the switching means 5 is stopped.
When operating - Midpoint of power supply → Output terminal 8b → Resistor rx
→8a→A current is generated from resistor 7 to the negative power supply. In this way, current can flow through the resistor rx as shown by the solid line and broken line arrows.In addition, the voltage waveform at the output terminal 8a is rz-Φ.The positive and negative voltages are approximately 11 equal to the positive and negative power supply voltages. Next, the operation of the specific circuit shown in FIG. 2 will be explained with reference to the operating waveforms shown in FIG. 3.

In Fig. 2, when the power is turned on, the multivibrator made up of transistors 11 and 12 oscillates, and the collector td of transistor 12, EX as shown in Fig. 3 (&).
A Luhalus sequence having a pOuelntial-like rise is generated. The collector of the transistor 13 has a waveform shaped as shown in FIG. transistor 13
[Thus, the transistor 14 and the transistor 17 are driven, and the waveform of the collector m becomes the waveform as shown in FIG.
5 is driven, and its waveform becomes as shown in FIG. 3(f). Further, the transistor 16 is driven by the transistor 16.

The waveform becomes as shown in FIG.
(f) in Figure 3 is a composite of the waveforms in Figure (C) and Figure 3 (6).
) is obtained.

In the positive/negative pulse generating circuit configured as described above, a PN switch is used as a switching means connected to the positive power supply 21.
By using an NPN transistor as a switching means connected to the negative power supply 22, positive and negative pulses with a sharp rising waveform can be obtained with a simple circuit.

This is because the transistor 16 connected to the negative power supply is driven by the transistor 13 via the transistor 14 and the transistor 15, but since the transistor 17 is a PNP transistor and the current is large, the rise time is slow. The fall is also slow due to carrier accumulation.
This is because the time becomes equal and the waveform becomes balanced.

FIG. 4 shows an embodiment of an electrical detection device using the present invention.

In FIG. 4, the positive and negative pulse generating circuit 31 is a rectifying diode, 32 is a resistor, and 33 is a capacitor. It is configured so that it occurs at both ends. This voltage is compared with a reference voltage formed by resistors 34 to 39 by voltage comparators 40 to 44.
By lighting up the light emitting diodes 45 to 49, the value of the resistance to be measured 20 is displayed. 6o to 64 are LICD current limiting resistors, and 65 is a positive power supply.

As an application of the electrical detection device configured as described above, by measuring the total resistance of the solution, it can be used as a taste measurement device or an animal ovulation prediction detection device. The present invention is driven by an oscillation circuit, two positive and negative power supplies, and an oscillation circuit. The switching means is connected to two positive and negative power supplies, and the switching means is connected by a resistor, and the connection point and the midpoint of the two positive and negative power supplies are connected to the full output terminal, so that the positive and negative pulse generation circuit can be created. This can be realized with a relatively simple configuration.

1, the switching means is PNP on the positive power supply side)
By using a transistor (NPN) on the negative power supply side, it is possible to obtain a positive and negative pulse train with a fast rise or fall and a clean waveform.Furthermore, by using the positive and negative pulse generation circuit described above, As a result, an electrical detection device capable of measuring the resistance of an electrolytic solution can be realized, and its effects are extremely impressive.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, and FIG.
The figure is an electric circuit diagram showing the configuration of a specific embodiment of the present invention.
FIG. 3 is an operational waveform diagram of each part of the electric circuit of FIG. 2, and FIG. 4 is an electric circuit diagram showing an embodiment of an electrical detection device using the positive/negative pulse generating circuit according to the embodiment of the present invention.

Claims (1)

[Claims] 0) An oscillation circuit, two positive and negative power supplies, a plurality of switching means driven by the oscillation circuit, connected to the positive and negative power supplies, the switching means connected by a resistor, and a connection point thereof. A positive/negative pulse generation circuit of an electrical detection device whose output terminals are the midpoint of two positive and negative power supplies. ? ) As a switching means - PNP on the positive power supply side
2. The positive and negative pulse generation circuit for an electrical detection device according to claim 1, wherein the transistor is configured using an NPN transistor on the negative power supply side.