JPS6161399A - Automatic flasher - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an automatic flasher for automatically turning on and off electricity to a load such as a lighting device according to ambient brightness.

<Prior art> In general, in this type of automatic flasher, in order to prevent an unstable state in which the load repeatedly turns on and off due to slight fluctuations in ambient illuminance, the switch is turned off when the ambient illuminance increases. It is necessary to provide a so-called hysteresis characteristic by creating a difference between the illuminance when turning off the lights and the illuminance when changing from turning off to turning on when the ambient illuminance decreases.

FIG. 3 shows a conventional example of the circuit configuration of an automatic flasher using CdS as a light receiving device for detecting ambient illuminance.

When the illuminance of the CdS light receiving section is lower than the lighting illuminance, CdS has a high resistance, so the point ■ is at a low potential, and the point ■ is also at a low potential, so the transistor Tr2t is turned on and current flows through the resistor R. . Then, the potential at the point ◎ rises, and the potential at the point ◎ also rises, so the transistor Tr22 is in an off state. At this time, the potential at point (2) is approximately Qv, and the transistor T r 23 is in an off state. Therefore, the resistance R
Current flows into the gate of thyristor Th2+ through 30, turning on thyristor rh21 and turning on triac T21 through diode bridge DB21. The load is then turned on.

When the illuminance of the CdS light-receiving section is equal to or higher than the extinguishing illuminance, the resistance value of the CdS decreases, so the potential at point (2) increases, and the potential at point (2) also increases, so that the transistor Tr21 is in an off state. At this time, points ◎ and ■ represent resistance Rx6. Ryu'l+
The potential is resistance-divided by Ryuf, and the potential at point ◎ turns on the transistor Trz2. transistor T
When rz2 is in the on state, current flows through resistor R2q,
The potential at point ■ rises and the transistor Tr23 turns on, so the transistor Tr23 draws the current flowing through the resistor R3゜ as well as the current from the gate of Cyrisk'rh2H as a collector current.
rh21 is turned off. When the thyristor Th21 is turned off, the triac T21 is also turned off, and the load is turned off.

The automatic flasher shown in Fig. 3 requires the above-mentioned complex circuit to provide hysteresis characteristics for turning on and off, and is also composed of a Zener diode ZD, a diode D, a capacitor C22, a resistor R2+, etc. The drawbacks were that it required a constant voltage circuit, had a large number of parts, and was expensive.

<Object of the invention> The present invention has been made in view of the above circumstances, and its object is to provide an automatic flasher with a simplified circuit configuration by including two solar cells as light receiving elements. be.

<Configuration of the Invention> In the present invention, an automatic flasher that controls power supply to a load according to ambient illuminance includes a switching element that controls power supply to the load, and a switching element that outputs a signal according to the surrounding illuminance. A first and a second solar cell, and a first signal based on the output signal of the first solar cell make the switching element conductive, and a second signal based on the output signal of the second solar cell. and circuit means for rendering the switching element non-conductive in response to the signal.

<Example> An embodiment of the present invention will be described below.

FIG. 1 shows the circuit configuration of an automatic flasher. The anode of the thyristor Th is connected to the AC power supply e, and the thyristor T
The cathode of h is connected to the lamp L, which is a load. The AC power supply e is also connected to the gate of the thyrisk Th via a resistor R, and to the anodes of programmable unijunction transistors (hereinafter referred to as unijunction transistors) PUTI and PUT2.

The cathode of solar cell SB2 is connected to the gate of unijunction transistor PUT2, and this solar cell SB
2 anode is unijunction transistor PUT
2, and a resistor R2 is connected in parallel with the solar cell SB2.

The cathode of the unijunction transistor PUT2 is connected to the cathode of the thyristor Th.

Further, the cathode of the solar cell SBI is connected to the gate of the unijunction transistor PUTI, the anode of the solar cell SBI is connected to the anode of the unijunction transistor PUTI, and a resistor R1 is connected in parallel with the solar cell SBI.

The cathode of the unijunction transistor PUTI is connected to the collector of the transistor Q.
The emitter of is connected to the cathode of thyristor Th.

The anode of a diode D is further connected to the AC power supply e, and the cathode of this diode D is connected to the resistors R3 and R4.
is connected to the cathode of the thyristor Th via the resistor R
3 and the resistor R4 are connected to the base of the transistor Q, and a capacitor C is connected in parallel with the resistor R4.

Next, the operation of the above circuit will be explained.

Unijunction transistors PUTI and PUT2 become conductive between the anode and cathode when the anode potential is higher than the gate potential by a predetermined value or more, and become non-conductive when the anode potential becomes lower than the cathode potential.

Solar cells SBI and SB2 are light receiving elements that detect illuminance, and the output characteristics of these solar cells SBI and SB2 are shown in FIG. The resistance value of the resistor R1 is selected so that the voltage across the terminals of the solar cell SBI becomes El (v) when the received light illuminance of the solar cell SBI is L+ (βX). The light receiving illuminance of battery SB2 is L2
(βX), the voltage across the terminals of solar cell SB2 is El
(V). This voltage E+ [v
) are unijunction transistors PUTI and PU
A voltage is selected at which the anode potential of T2 becomes higher than the gate potential and the gate current brings conduction between the seven nodes and cathodes of unijunction transistors PUT1 and PUT2.

Now, when solar cells SBI and SB2 are not irradiated with light, no voltage is generated between the respective terminals of resistors R1 and R2, so both unijunction transistors PUTI and PUT2 are anodes.

The gates are at the same potential, and the anodes and cathodes of the unijunction transistors PUT1 and PUT2 are non-conductive. Therefore, during the positive half cycle of AC from the power source e, current flows through the resistor R to the gate of the thyristor Th, the thyristor Th becomes conductive, and the current flows from the power source e through the anode and cathode of the thyristor Th to the lamp L. Powered by When the alternating current from the power source e is in a negative half cycle, the thyristor Th is in a non-conducting state.

In the positive half cycle of AC of the power source e, when the gate current of the thyristor Th is not applied for the reason described later and the thyristor Th is in a non-conducting state, the thyristor T
A voltage ep is applied between the anode and cathode of h through a load.
is applied. Then, this voltage ep is rectified by a diode D to generate a DC voltage ER between the terminals of the resistor R4. The resistor R3 is a voltage dividing resistor for obtaining this voltage ER, and the capacitor C is for smoothing the voltage rectified by the diode D to obtain the above-mentioned DC voltage ER between the terminals of the resistor R4.

The resistance values of the resistors R3 and R4 have the relationship R3+R4>>rl with respect to the internal resistance r2 of the load, so that the power supplied from the power supply e to the load through the resistors R3 and R4 can be ignored, and
It is determined so that the transistor Q can be rendered conductive by the voltage ER generated across the resistor R4.

As described above, when the solar cells SBI and SB2 are not irradiated with light, the thyristor Th is in a conductive state during the positive half cycle of the alternating current of the power source e, and no direct current voltage ER is generated between the terminals of the resistor R4.

Next, the illuminance of the light-receiving surfaces of solar cells SBI and SB2 is Ll
(j!
E+ (v), and the anode and cathode of the unijunction transistor PUTI become conductive.

However, in the positive half cycle of the alternating current of the power source e, the thyristor T
h is in a conductive state, the voltage ER across the glass of resistor R4
does not occur, and transistor Q is in a non-conducting state. In addition, at this time, the voltage between the terminals of the resistor R2 becomes B2 (V) as shown in FIG. 2, but since B2<E+, the anode and cathode of the unijunction transistor PUT2 are in a non-conducting state. be.

Then, when the illuminance reaches L1 (lx), power supply to the lamp L, which is a load, is continued.

After that, when the illuminance of the light-receiving surfaces of solar cells SBI and SB2 further increases to L2 (βX), solar cells SB2
Due to the electromotive force, the voltage between the terminals of the resistor R2 becomes El (v), and the anode and cathode of the unijunction transistor PUT2 become conductive. As a result, the gate of thyristor Th.

Unijunction transistor PUT2 between cathodes
The current that had been supplied to the gate of thyristor Th through the resistor R is now connected to the thyristor Th via the unijunction transistor PUT2.
The thyristor Th becomes non-conducting after being extinguished by the negative half cycle of the alternating current of the current.

Then, power supply to the load is stopped.

At this time, since the thyristor Th is in a non-conducting state even in the positive half cycle of the alternating current of the power supply e, a voltage E is generated between the terminals of the resistor R4, and the transistor Q becomes conductive. Therefore, between the gate and cathode of the thyristor Th, together with the unijunction transistor PUT2,
Both unijunction transistor PUTI and transistor Q are shorted.

After that, when the illuminance on the light-receiving surfaces of solar cells SBI and SB2 decreases to below B2 (/x) and becomes above + (lx), the voltage between the terminals of resistor R2 becomes below El [v]. , the unijunction transistor PUT2 becomes non-conductive. On the other hand, the voltage between the terminals of resistor R1 is E+
(v) Since the above is the case, the unijunction transistor PUTI continues to be in a conductive state, and since the transistor Q is also in a conductive state, the thyristor Th continues to be in a non-conductive state. And the power supply to the load remains stopped.

Next, when the illuminance on the light-receiving surfaces of solar cells SBI and SB2 further decreases to less than L+ (βX), the voltage across the terminals of resistor R1 becomes less than El (v), so unijunction transistor PUTI The gate of thyristor Th becomes non-conductive.

No short circuit between cathodes. And thyristor Th
A current flows through the resistor R to the gate of the thyristor Th.
becomes conductive, and power is supplied to the load. At this time, the voltage ER across the resistor R4 disappears, and the transistor Q becomes non-conductive.

The above operations are summarized as the operations of automatic flashers under the actual environment as shown in the following table.

That is, when the illuminance increases, the illuminance increases to B2(j!
x) When the light is turned off and the illuminance decreases, the light is turned on at Ll (j'x), where the illuminance is lower than B2 (lx). In this way, by making a difference in the illuminance when the lights are on and when they are off,
Provides hysteresis characteristics.

The illuminance LL (nx) and B2 (j
! x) can be set arbitrarily depending on the resistance values of the resistor R1 and the resistor R2.

<Effects of the Invention> As explained above, in the present invention, the switching element is brought into a conductive state and a non-conductive state by the first and second signals based on the respective output signals of the second solar cell. Because of this, it is possible to realize an automatic flasher with a simple circuit, which lowers the cost and simplifies the manufacturing process.
By using a solar cell as a light receiving element, low illuminance (
In other words, it has an excellent ability to stop power supply to the load until the solar cell no longer has any electromotive force, and also has the power saving feature of not consuming power in a no-load state.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is a graph showing output characteristics of a solar cell, and FIG. 3 is a circuit diagram showing a conventional example. Th-・-Sirisk L-Load SB1. SB2~・Solar cell PUTl, PUT2−・・Programmable unijunction transistor R, R1, R2, R3, R4−−Resistor Q−・−Transistor D−・Diode C −Capacitor

Claims (1)

[Claims] (1) In an automatic flasher that controls the power supply to the load according to the ambient illuminance, a switching element that controls the power supply to the load, and first and second solar lights that output a signal according to the ambient illuminance. A first signal based on the output signal of the battery and the first solar cell makes the switching element conductive, and a second signal based on the output signal of the second solar cell turns the switching element on. An automatic flasher characterized in that it comprises circuit means for bringing it into a non-conductive state.