JPS58166693A - 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 The present invention relates to an automatic flasher that detects ambient illuminance using a photoconductive cell and turns off power to a load.

Conventionally, various circuits have been employed in this type of automatic flasher, and two conventional examples will be explained based on Figures 1 and 2.

First, what is shown in FIG. 1 will be explained. Power supply (1)
A triac (2) and a load (3) such as a lamp are connected to the triac (2).
) and a diac (6) serving as a trigger element are connected in parallel, and a resistor (7) is connected to one maximum of this diac (6) and Ts and 0ISIK of the triac (2).

In such a configuration, when a predetermined voltage is applied to the power supply 11(1)K, a power supply voltage is generated between Ts and Tm of the triac (2) via the load (3). On the other hand, T.I.T.
mK is connected to Cd8 (4) and resistor (7), and voltage V at point A is a value divided by CdS (4) and resistor (7). In addition, since point A is connected to the gate of the triac (2) via the diac (6), when Vmu exceeds the breakover voltage of the diac (6), the diac (6) becomes conductive and the triac (2) is connected to the gate of the triac (2). )
Trigger current flows through.

Now, assuming that the ambient light is getting darker, CdS
The resistance value of (4) increases, and vmu also increases proportionally. When the voltage V reaches the trigger voltage, the diac (6) becomes conductive, and at this time, the charge stored in the capacitor (5) is discharged, turning on the triac (2).

When this triac (2) is turned on, the voltage across TlTs becomes almost zero9, and this state is maintained until the next half cycle begins.

The next half cycle similarly starts with triac (2) OFF, and when vm exceeds the trigger voltage, diac (
6) is ONL, and as a result, the capacitor (5) K discharges the charged charge and tries book (2) LPON.

On the other hand, when the ambient illuminance becomes brighter, the resistance value of CdS (4) becomes smaller, vm does not exceed the gate voltage, and the try book (2) is up to 11, which is OFF. In this case, when the load (3) has a large inductance, that is, when the power factor is low, the trigger current increases due to the time that the triac (2) is ON, that is, the discharge from the capacitor (5). During the flowing time, the main current of the triac (2) may not reach the holding current value Kl that keeps the triac (2) ON due to a phase lag. Therefore, −
The ventral trigger nine triac (2) is turned OFF again, and voltage is again applied across the triac (2), which causes the capacitor (5) to charge again, and when this exceeds the trigger voltage, the triac (2)tQN
do. This operation is repeated several times within a half cycle, but has the disadvantage that the triac (2) cannot be moved when the inductance is large.

Next, in the case shown in FIG. 2, a partial voltage of CdS (4) and a resistor (8) R1 is applied to the gate of a triac (9), and this triac (9) is connected to a resistor (8a
) is connected in series with the gate of triac (2). Therefore, when the surroundings become dark, Cd5(4
) becomes larger and the trigger try book (
9), and when it opens, the main triac (
The gate current of 2) flows, and it flows to the side. When the JII 11 area becomes bright, the triac (9) cannot be turned on, and the main triac (2) also remains off.

In this circuit, even if the load (3) has a large intuffance, the trigger trybook (9) remains at 1, so the triac (2) remains ON even if there is a phase lag in the current.
can. However, since the trigger current of the triac (2) usually requires 20 mJ or more, the loss due to the trigger current becomes very large. For example, in a 100V circuit, the loss of the trigger circuit PLO811 = 100VX 20m
Al2W will be consumed at 08:00. This goes against the purpose of using semiconductors for automatic flashers to reduce power consumption.

To solve this problem, a full-wave rectifier circuit is connected between the gate of the triac and the load side, and a photoconductive cell is connected between the positive side and one side of the full-wave rectifier circuit. -0FF
It is conceivable to connect a thyristor that is controlled by

Although this type of device satisfactorily solves the above-mentioned drawbacks, the gate sensitivity of thyristors changes greatly depending on the temperature,
This has the disadvantage that the characteristics change.

The present invention has been made in view of these points, and an object of the present invention is to provide an automatic flasher that consumes less power and does not change its characteristics due to temperature.

In the present invention, a thyristor is connected to the gate of a triac that controls energization to a load via a full-wave rectifier circuit, and a high gain switching element whose operation is controlled by a photoconductive cell is connected to the gate of this thyristor. 0 of
N-OFF is performed in a constant state regardless of the gate sensitivity, so that it is not affected by temperature, and the power consumption is extremely low. be.

A first embodiment of the present invention will be described based on FIG. t
First, a triac αυ and a load (6) are connected to a power supply αQ. A full-wave rectifier circuit (to) is connected between GT and Tm of this triac C11). A thyristor CL4 is connected with the anode located on the + side of this full-wave rectifier circuit (to) and the cathode located on the -111 side. A resistor R1 (
), R3 resistance (g), R4 resistance (b), R@
The gate of the thyristor (b) is connected to the connection midpoint of the resistor a through the resistor Re. 9. A PUT (e), which is a high gain switching element, is connected between the connection midpoint of the resistor (2) and the cathode of the tillister α. The gate of this PUT 9IJ and the resistance (to) (to)
A resistor R3 (c) is connected between the connection midpoint of
And, in the G- of PUT (E), there is C which is a photoconductive cell.
dS @ is connected.

Furthermore, the resistor (C) and the CdS @ and K are connected to a Zener diode that constitutes a constant voltage circuit. In this configuration, PUT (E) is connected to the thyristor α
The gate sensitivity is very high compared to ◆, and the gate current can be reduced to tl.
I don't really need it. Therefore, connect K Cd5 (2) to G- of PU'l), and connect the anode of PUT 94 to the gate of thyristor α◆ via resistors (B) and (to). The voltage VA applied to the anode of Il(E) is as follows: Vz is the Zener voltage of the Zener diode 61o.

Further, the gate O voltage vG of ptrr(e) is as follows.

R.

Vo 聰Vj　X□ R fable + RO However, RO is the resistance value of CdS@.

Therefore, when VA>G, pu'r 61O is ONL in terms of switching, and when VA<Vo, it is OFF.

When PUT- is ON, the voltage is divided by the resistance (B) ring at approximately O, SV, so firis pG4 is OFF L
, PUT IIJ is OFF, and a voltage higher than the gate turn-on voltage of the thyristor α◆ is applied, and the thyristor (R4
turns on.

When the thyristor α♦ is on its side, the triac α is also turned on, but at this time, the voltage across G-Tm of the triac cI is small, and the power consumption during copying is extremely small. In addition, since thyristor a4 is turned on by being triggered by PU'l)K, there is no effect of fluctuations in gate sensitivity due to temperature changes.Next, based on FIGS. 4 and 5, A second embodiment will be explained. The same parts as in the previous embodiment are given the same reference numerals, and the explanations are omitted. In this embodiment, a resistor R1 (c) and a resistor R1 are connected between the midpoint of the connection between the resistor resistance (
C) and a time constant circuit consisting of a capacitor (2) called C.
is connected.

In such a configuration, if the voltage at the connection point between the resistor (c) and CdS @ is Vz, then the voltage at the connection point between the resistors (c) and (c) is Vo.
The change in is delayed from vl by a time constant determined by the resistance and the capacitor. The operation of PUT H is VA > VG TE GJ, VA < VG TE OFF
Therefore, as the resistance Ro of tCds(2) increases, F'UT gO turns ON every cycle in the region addressed to NU, like VA in FIG. When this is ON, the instantaneous Ve becomes zero potential and is discharged from the capacitor via the resistor) with a time constant of Rs and C. Therefore, as shown by Vo, due to the discharge from the resistor (2) to the PUT (1), the capacitor voltage Vo becomes lower than when there is no discharge.

Since a decrease in Va means a decrease in Vo isometrically, it is not possible to turn off the PUT (a) at the specified illuminance, and a hysteresis effect t that changes the illuminance when turned on and the illuminance when turned off is also provided. is possible.

Now, the resistance value Rv of resistor (2), the ratio of R can be set to our own specifications, Rv: 84-1 g 2 to 10
Experimentally, the position is suitable.

The present invention provides an arrangement in which the operation of the triac for controlling the current to the load is performed by a thyristor that is turned on and off by a photoconductive cell as described above. A full-wave rectifier circuit and a thyristor are connected to the thyristor, and the operation of the thyristor is controlled by a high-gain switching element such as a two-stone transistor to which a photoconductive cell is connected. Switching is performed with little influence of temperature, and as a result, even parts that are affected by temperature, such as thyristors, do not change their characteristics due to temperature and are stable, and the power consumption during triac OON is also low. Furthermore, by adding a time constant circuit, it is possible to easily create a difference in illuminance between when the light is turned on and when the light is turned off.

[Brief explanation of drawings]

1 and 2 are circuit diagrams showing a conventional example, FIG. 3 is a circuit diagram showing a first embodiment of the present invention, and FIG. 4 is a circuit diagram showing a second embodiment of the present invention, FIG. 5 is a waveform diagram thereof. 11...Triac, 12...Load, 13...
Full-wave rectifier circuit, 14...thyristor, 15-19...
・Resistance, 20...PUT (high gain switching element), 22...Cd8 (photoconductive cell), 24~2T・
・Resistor, 26...Capacitor, 27...Time constant circuit Application person Tokyo Electric Co., Ltd. - House L7-, figure 5)

Claims (1)

[Claims] l The triac and the load are connected in series lI! A photoconductive cell is provided to control the triac 0QN-OFF and to turn on and off the negative fr according to the degree of the surrounding layer of the triac. and a thyristor having an anode connected to the positive side and a cathode connected to the negative side of the gold wave rectifier fILwA path,
Resistors are connected between the anode and gate of ζtVt Iris I and between the gate pot cathode, and a gain switch element such as Hπ is connected in parallel with a part of these resistors. An automatic flasher that connects photoconductive cells and uses 4 types of light. 2. A photoconductive cell is connected in series with a light source and a load, and the light source is turned on and off by controlling the light source 0QN-OFF according to ambient illuminance, and the light source and the load are connected in series. A nine-kin wave rectifier circuit is connected between the gate and the load, and a thyristor is provided, in which seven nodes are connected to the positive side of the gold wave rectifier circuit and a cathode is connected to the negative side.・Connect a resistor to the cathode and connect some of these resistors in parallel with K.
An automatic flasher characterized in that a high gain switching element such as a PUT is connected, and a time constant circuit consisting of a resistor and a capacitor and the photoconductive cell are connected to the gate side of the high gain switching element. 3 A time constant circuit is formed by two resistors connecting between the photoconductive cell and the high gain switching element, a capacitor connected to the connection point between these resistors, and a resistor on the photoconductive cell side. 8. The automatic flasher according to claim 8, wherein a resistance value of the resistance on the high gain switching element side and the resistance on the high gain switching element side is set to 1:2 to 10.