JPS58103655A - Humidity control circuit - Google Patents

Abstract

PURPOSE:To improve the responsiveness of a humidity control circuit by forming an oscillating circuit by the use of an element of which electrostatic capacity changes with relative humidity, and comparing the voltage charged by the pulses of the oscillating circuit and a set voltage to control humidification. CONSTITUTION:A humidity detecting element 10 is so constituted that its electrostatic capacity increases with an increase in relative humidity and that said capacity changes roughly linearly in a practicable use range. A serial circuit of resistors (R) 5, 6 is connected via a switch 2 to an electric power source 1, and the connecting point (c) of the R5, 6 is connected to the positive input terminal of a differential amplifier 9. The output point (f) of the amplifier 9 is connected via R11 to the point (c) and via R12 to the negative input terminal, and the element 10 is connected to the point (e) and to the other terminals of the R6, to form an oscillating circuit. The oscillating output drawn out through R13, and charges a capacitor 17. The charged voltage thereof is applied to a differential amplifier 19 and is compared with the voltage set by R7, 8. The output of the amplifier 19 is connected via a transistor 4 to a relay 3 to drive a humidifier. Therefore the comfortable humidification is accomplished with good responsiveness.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is applied to a humidity control circuit, and in particular controls humidity using a humidity detection element whose capacitance changes with relative humidity. In general, when forced air supply/exhaust hot air fans are used, indoor air can dry out and have a negative impact on the human body and furniture, which is why humidification is necessary.

However, the reality is that it is not possible to adjust the humidity properly due to either too much humidification or not enough humidification.

The present invention solves the conventional problems by using a humidity sensing element whose capacitance changes with relative humidity.

An embodiment of the present invention will be described below with reference to the accompanying drawings.

10 in Figure 1 is a humidity detection element, and as shown in Figure 2, as the relative humidity increases, the capacitance of the capacitor increases, and especially in the practical range of 20 to 80%, it changes almost linearly. ing. FIG. 1 shows a circuit for adjusting indoor humidity using such a humidity detecting element 1o. , in FIG. 1, power supply 1 and switch 2: 1 point; relay 3; transistor 49. Point b depicts a closed loop,
It constitutes a load circuit with power supply 1. Between points a and b, resistance is 6; 0 point: resistance 6. Variable resistor 7 for humidity setting; 6 points;
A series circuit of resistors 8 is connected. Further, the positive input terminal of a first differential amplifier (hereinafter referred to as an operational amplifier) 9 is connected from the 0 point, and one end of the humidity detection element 10 is connected to the negative input terminal 6 points.

A resistor 11 is connected to the output terminals f and 0 of the operational amplifier 9, and a resistor 12 is connected to the output terminals f and 6. From point f, resistor 13; capacitor 14: point g (the anode is point b)
A series circuit of diode 15 is connected, and further from point g (
Anode side is connected to point g) diode 16: point h; a series circuit of capacitor 17 is connected. capacitor 17
A resistor 18 is connected in parallel. The positive input terminal and negative input terminal of the No. 10 differential amplifier (hereinafter referred to as operational amplifier) 19 are connected to point d, and from the output terminal i, a resistor 20 is connected.
Point j: A series circuit of resistor 21 is connected. The base of the transistor 14 is connected to the point j. It should be noted that a diode 2□2 with the one-point side as the bottom is connected to the relay 3 for protection. Further, although this relay 3 is not shown, it drives a humidifier. The operation of this circuit is such that when the switch 2 is closed, a voltage is applied to the circuit of the resistor 6.6, and the voltage is maintained at a zero point. At this point, the humidity sensing element 1o has no charge yet, so the 0 point is 0.
potential, so the f point is high. (In addition,
The resistor 11 makes the potential at point C slightly higher than that of the resistor 6 alone. ) Next, the humidity detection element 1o begins to be charged by the resistor 12, and the potential at the 0 point begins to rise. Then, when the potential at the 0 point becomes slightly larger than that at the 0 point, the output of the operational amplifier 9 becomes low, and the f point also becomes low. As a result, the potential at the 0 point decreases, and therefore, the potential at the 0 point becomes higher, and the humidity detection element 10 begins to discharge through the resistor 12. Then, when the potential at point 6 becomes lower than the potential at point 0, the output of operational amplifier 9 becomes high, and point f also becomes high again, returning to the initial state. In other words, the f1 warehouse is shown in Figure 3a.
It oscillates like this. In this case, the oscillation frequency changes depending on the capacitance of the humidity detection element 1o. That is, when the capacitance is large, the frequency becomes low, and when it is small, the frequency becomes high.

Next, a in FIG. 3 shows the oscillation situation of the operational amplifier 9 (point f). Next, b shows the state of charging and discharging of the capacitor 14. When the f point is high, the capacitor 14 shows charging characteristics, and when it is low, it shows discharging characteristics. Therefore, the current flowing through the diode 16 is a pulsed current like C, which charges the capacitor 17. The C characteristic has the same waveform even if there are as few as six frequencies, so the h point gradually rises depending on the number of pulses, and after a while it reaches a constant potential determined by the value of the resistor 18. That is, the potential at point h is determined by the oscillation frequency of the operational amplifier 9 (capacitance of the humidity sensor), and when the humidity is high, the capacitance becomes large, the oscillation frequency becomes small, and the potential at point h becomes low. Conversely, when the humidity is low, the potential at point h becomes high. Comparator 19 compares the potential at point h and the potential at point d determined by the variable resistor, and if the humidity is lower than the set value, comparator 1
9 is turned on, the relay 3 operates, and the humidifier is driven. When the humidification increases the humidity and the capacity of the humidity detection element 1o increases, the operational amplifier 19 is turned off to stop driving the humidifier.

As described above, according to the present invention, optimal humidification can be performed, and since humidity is detected by capacitance, the response is quick and comfortable humidification can be performed.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is a humidity characteristic diagram of a humidity detecting element, and FIGS. 3 a to 3 c are diagrams explaining the operation. 3... Relay, 7... Variable resistor, 1
0... Humidity detection element, 19... Operational amplifier. Name of agent: Patent attorney Toshio Nakao and 1 other person
1l1 2 112 figure left opening X fake (2) 183 figure

Claims (1)

[Claims] A humidity adjustment circuit that uses an element whose capacitance changes with relative humidity to form an oscillation circuit, and performs humidification control by comparing the charging voltage of the charging circuit, which is charged by the pulses of the oscillation circuit, with the set voltage.