JPS5834720Y2 - automatic flashing device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an automatic blinking device that automatically blinks a lighting lamp depending on the surrounding brightness.

Conventionally, this type of automatic flashing device is as shown in Fig. 1, in which the DC voltage obtained by rectifying and smoothing the AC power supply AC with a diode D1 and a capacitor C is applied to a Zener diode Z via a resistor R9. A Zener voltage, that is, a stabilized DC voltage VC, is applied to both ends of the resistors R2 and R3 connected in series, and a reference voltage (2) obtained by dividing the voltage by the sheet resistance is applied to the emitter, and the stabilized DC voltage V is applied to the emitter.

The collector output of the light/dark detection transistor Q1, whose base is applied with a divided voltage v1 divided by an alternating current converter P such as a transistor and a resistor R1, is connected to the SCR control transistor C2-. and enter
The SCR control transistor Q2 controls the 5CR(S) that triggers the triac T, and the triac T causes the lighting to blink.The base of the light/dark detection transistor Q1 and the SCR control transistor A resistor R4 is inserted between the two resistors.

The operation of the conventional example will be explained below.

When the surroundings become dark now, the resistance of the photoelectric conversion element P increases, and the divided voltage ■1 applied to the base of the light/dark detection transistor Q1 decreases, and this divided voltage V1 becomes the reference voltage ■2.
When the temperature becomes lower, that is, when the surrounding brightness falls below a certain level, the light/dark detection transistor Q1 becomes conductive, and the SCR control transistor charge current flows. 5CR(S) is fired through the control transistor 2.

When this 5CR(S) becomes conductive, a trigger current for the triac T flows from the alternating current power source AC through the illumination lamp and the rectifier circuit, the triac T becomes conductive, and the illumination lamp lights up.

Next, when the surroundings become brighter, the resistance of the photoelectric conversion element P decreases, and the divided voltage ■1 applied to the base of the light/dark detection transistor Q1 increases, and this divided voltage ■1 becomes the reference voltage. When the voltage exceeds V2, the light/dark detection transistor Q1 is reverse biased and cut off, and the SCR control transistor Q2 is cut off.

Therefore, 5CR(S) and TRIAC T are not fired and the illumination light is turned off.

By the way, the key of the light/dark detection transistor Q1 and the SCR
Since the collector of the control transistor Q2 is connected to the resistor R4, when the surroundings become dark and the resistance of the photoelectric conversion element P increases, the light/dark detection transistor Q becomes conductive, and the photoelectric conversion element at the time when the illumination light is turned on. Resistance value R of P
A and the resistance value RB of the photoelectric conversion element P at the time when the surroundings become bright and the illumination light is turned on are different, and the blinking operation of the illumination light due to the brightness of the surroundings has a so-called hysteresis characteristic.

In this case, the resistance RA of the photoelectric conversion element P when turned on and the resistance R8 of the photoelectric conversion element P when turned off satisfy the following relationship.

However, VBE is a voltage drop between the base and emitter of the light/dark detection transistor Q1.

As is clear from the above equation, by changing the feedback resistor R4, it is possible to change the hysteresis width, that is, the difference between the ambient brightness when the lighting lamp is turned on and the surrounding brightness when the lighting lamp is turned off. There is.

In such a conventional example, when adjusting the hysteresis characteristic of an automatic flashing device, the time when the light is turned on and the time when the light is turned off is set by a resistor R.
,, R4 will change accordingly, so if you change the feedback resistor R4 to adjust the turn-off point after adjusting the turn-on point, the turn-on point will also change accordingly. This has the disadvantage that it is difficult to adjust the hysteresis characteristics.

In addition, the SCR control transistor Q2 becomes conductive, and the 5CR (
When S) is triggered, a current flows through resistor R6 in addition to the trigger current, increasing the current flowing through the control circuit of 5CR(S), which has the drawback of increasing power loss due to resistors R9 and RIO. .

The present invention aims to solve the above-mentioned drawbacks.

Examples will be described below using figures.

Figure 2 shows an embodiment of the present invention, in which a stabilized DC voltage ■.

While applying a reference voltage 2 obtained by dividing the voltage by two series-connected resistors R2 and R3 to the emitter,
The collector output of the light/dark detection transistor Q1 to which the divided voltage V1 obtained by dividing the stabilized DC voltage VC by the resistor R1 and the photoelectric conversion element P is applied to the base is connected to the SCR in parallel between the gate and cathode of 5CR(S). In an outdoor light automatic flashing device in which the voltage is applied to the base of the control transistor Q2 and 5CR(S) controls the illumination light flashing switching element T made of a triac, the emitter of the light/dark detection transistor Ql and the 5CR(3) A series circuit consisting of a resistor R4 and a reverse current blocking diode D2 is inserted between the anodes.

In the figure, R1 to R16 are resistors, C1 is a capacitor, and N is a neon lamp.

The operation of the embodiment will be explained below.

Now, when the ambient brightness changes, the resistance of the photoelectric conversion element P changes according to the brightness, and the divided voltage (1) also changes.

When this divided voltage ■1 becomes less than the reference voltage V2, that is, when the surrounding brightness exceeds a certain brightness, the light/dark detection transistor Q1 is forward biased and becomes conductive.
Since the SCR control transistor Q2 is also conductive, 5CR
(S) is short-circuited between the gate and cathode, and SCR(S)
And the triac T is not fired and the illumination light is turned off.

On the other hand, when the ambient brightness falls below a certain level, the resistance of the charge conversion element P increases and the divided voltage ■1 increases, so the light/dark detection transistor Q1 is reverse biased and shut off, controlling the SCR. Since the transistor Q2 is also cut off, a trigger current flows through the SCR(S) through the resistor R5, and 5CR(S) becomes conductive, triggering the triac T and lighting the lamp.

By the way, when 5CR(S) becomes conductive, the resistor R4 becomes the resistor R
3 and the reference voltage 2 will be lowered, so the ambient brightness at the time the light goes off and when the automatic flasher turns on will be different from the conventional example. They will have similar hysteresis characteristics.

In this case, in order to adjust the hysteresis characteristic, for example, the lighting point is adjusted with the resistor R1, and the lighting point is adjusted with the resistor R4, so that the same points can be adjusted independently.

Also, cut off the SCR control transistor 2 and 5CR.
When (S) is conducting, the current flowing through resistor R5 is only the trigger, and there is no current flowing through resistor R6 as in the conventional example, so the current flowing through the control circuit of 5CR(S) becomes small, and resistors R9, For R10, it is possible to use a small one with a small current capacity.

The present invention is configured as described above, and in an automatic flashing device having hysteresis characteristics, the lighting point and the turning point can be adjusted independently, so it has the advantage that the hysteresis characteristic can be easily adjusted, and the SCR
This has the advantage that power loss in the control circuit can be reduced.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a conventional example, and FIG. 2 is a circuit diagram of an embodiment of the present invention. L is a lighting lamp, T is a switching element, R1-R16 is a resistor, P is a photoelectric conversion element, Ql, Q2 are transistors, (
S) is SCR.

Claims (1)

[Scope of utility model registration request] A reference voltage obtained by dividing the DC power supply voltage by two resistors connected in series is applied to the emitter, and a divided voltage obtained by dividing the DC power supply voltage by a resistor and a photoelectric conversion element is applied to the base. The collector output of the detection transistor is applied to the base of the SCR control transistor connected in parallel between the gate and cathode of the SCR, and the
An automatic flashing device for outdoor lights in which a switching element for lighting flashing is controlled by a CR, and a series circuit of a resistor and a backflow blocking diode is inserted between the emitter of a light/dark detection transistor and the anode of an SCR. .