KR790002035Y1 - Fire senser with constant-voltage circuit - Google Patents

Abstract

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Description

Smoke detector with constant voltage circuit

1 and 2 are circuit diagrams of a fire detector having a conventional constant voltage circuit.

2 to 6 are circuit diagrams of different embodiments of the present invention, respectively.

Since most of the conventional fire detectors are of a type in which electrical contacts are closed by heat of fire, the power supply in the receiver or repeater does not need to be a constant voltage power supply, and thus the fluctuations in the voltage supplied to the fire detectors are considerably wide. This was supposed to be great. By the way, recently, various fire detectors using semiconductor circuits have been developed. Since such detectors often require a constant voltage power supply, it is necessary to connect them to a conventional receiver or repeater having a power source having a variable voltage. Some constant voltage circuitry needs to be inserted into the detector.

There are two forms of inserting the constant voltage circuit into the fire detector, as shown in Figs. 1A and 1B. In this figure, (D) is a fire detection section (hereinafter referred to simply as a fire detection section) including an amplification circuit, (S) is a switching circuit, and (C) is a constant voltage circuit. This design belongs to the form of FIG. 1A of this figure. In addition, in the case of the type of FIG. 1A, the constant voltage circuit (C) does not necessarily need to be embedded in the detector, and may be installed separately from the detector.

As an example of the constant voltage circuit C suitable for the form of FIG. 1A, the series transistor type constant voltage circuit shown in FIG. 2 is known. In this figure, the constant voltage circuit C includes a transistor Tr connected in series with a positive line, and a Zener tywood Z connected in parallel with the switching circuit S through a base and an emitter of Tr. And the resistance R in the base current circuit of Tr, but the problem when designing the circuit of FIG. 2 is the value of the resistance R. In this figure, if it is sufficient to supply from the constant voltage circuit C the usual monitoring current consumed by the fire detection unit D and the switching circuit S, the value of the resistor R may be considerably high. When the switching circuit (S) is activated during operation and the line is shorted, the current required to operate the receiving relay in the receiver or the relay in the repeater is connected to the line connecting the detector and the receiver or repeater through the constant voltage circuit (C). You must distribute. Therefore, when the switching circuit S is operated during the operation of the detector, the base current necessary for distributing the current higher than the touching current of the receiving or relay relay can be distributed through the resistor R to the transistor Tr. Since the value of the resistor R must be set so that the value of the resistor R becomes quite small. As a result, the current consumed by the constant voltage circuit C in the monitoring state increases in general and the monitoring current of the entire detector also increases considerably, thus avoiding a drawback in that the number of detectors that can be connected in parallel on the same line is limited. .

The design of the present invention reduces the current flowing through itself in the state of ordinary monitoring as much as possible, and at the same time, distributes the electric current required to reliably operate the receiving or relay relay in the line during the operation of the detector. An object of the present invention is to obtain a fire detector having a constant voltage circuit, which will be described in more detail based on the embodiments shown in FIGS. 3 to 6 as follows.

The fire detection unit (D) in FIG. 3 is a series circuit of deoeo Mr (R _th) and a normal resistance (R ₁₎ that the resistance is reduced by the fire to heat, the output includes a capacitor (C ₁₎ in parallel with the resistance (R ₂ ) and (R ₃ ) are placed and connected in parallel with this, and conduction is controlled by the potential of the connection point between the dermater (R _th ) and the resistor (R ₁ ) so that the usual bladder resistance ( And a transistor (Tr ₁ ) biased by cutoff by R ₂ ) and (R ₄ ), and the switching circuit S includes the capacitor C ₂ in parallel with the current detector D. A transistor provided with a resistor R ₅ provided therein and connected to both ends of the transistor Tr ₂ controlled by conduction by the output voltage of the resistor R ₂ of the detector D and the resistor R ₅ . a transistor whose emitter and base connected to the transistor collector his (Tr ₂₎ It is a transistor (Tr ₃₎ connected to the base. In addition, the constant voltage circuit C connected between the switching circuit S and the input terminals a and b connects the base and the emitter of the transistor Tr ₄ connected in series in the positive line. and a through circuit (S) and a zener diode (Z) connected in parallel, an input terminal (a) and a transistor (Tr ₄₎ a resistor connected between the base of (R ₇₎ and a resistor (R ₇₎ and parallel A transistor connected to the base and the emitter, which is connected to both ends of the resistor R ₆ and constitutes a transistor Tr ₅ which forms a circuit for amplifying the collector current of the transistor Tr ₄ , and the resistor R ₇ ) is set to a value in which only the normal monitoring current is distributed to the detector D and the switching circuit S, and the resistor R ₆ is connected to the transistor Tr _{5 as the} normal monitoring current. At the same time, it is set to a small value that cannot be achieved, and the switching circuit S is operated to Only ensured by the collector current of the transistor (Tr ₄₎ a transistor (Tr ₅₎ is placed by selecting a size of as much as to be able to conducted. When the circuit constant is set in this way, since the value of the resistor R ₇ is extremely high in the normal monitoring state, the monitoring residual of the detector flowing through the constant voltage circuit C is limited and the transistor Tr when the detector is operated. relay in the receiving relay or repeater in ₅₎ is the resistance (R ₇₎ short-circuit by interconnecting it can supply a sufficient base current to the transistor (Tr _4), the collector current of the transistor (Tr ₄₎ of is a sufficiently large value receiver The relay can be operated reliably.

4 is a circuit diagram of still another embodiment of the present invention, in which the circuit C includes a transistor Tr ₄ and a resistor R ₆ connected in series with each other in a negative line, and an emitter of the transistor Tr ₄ . And a Zener diode Z connected in parallel with the switching circuit S through the base, a resistor R ₇ connected between the collector and the base of the transistor Tr ₄ , and the input terminals a and b. Is a thyristors connected between the transistors and their gates and cathodes are connected to both ends of the resistor R ₆ to form a circuit for amplifying the collector current of the transistor Tr ₄ . The value of (R ₇ ) is increased so that only the normal monitoring current flows through the transistor Tr ₄ , and the resistance R ₆ is small enough that the thyristor SCR cannot conduct to the normal monitoring current. While setting to a value, the switching circuit (S) Only versification is chosen as large as there are uihang W reliably thyristors (SCR) to the collector current of the transistor (Tr ₄₎ can be conducted.

In this way, in the normal monitoring state, the monitoring current of the detector flowing through the constant voltage circuit C is reduced by the high resistance of the resistor R ₇ , and during reception of the detector by the conduction of the thyristor SCR. Alternatively, the electric current required to reliably operate the relay relay can be distributed to the line.

5 is a circuit diagram of another embodiment of the present invention, in which the constant voltage circuit C includes a resistor R ₆ and a transistor Tr ₄ connected in series with each other in a positive line, and the resistor R ₆ and a transistor. (Tr ₄₎ of the base, and the Zener diode (Z) connected in parallel with Switching circuit (S) through the emitter, the resistor (R _6), and a thyristor connected in series circuit in parallel with the transistor (Tr ₄₎ Its gate and cathode are composed of a thyristors (SCR) connected to both ends of the resistor (R ₆ ) to form a circuit for amplifying the emitter current of the transistor (Tr ₄ ), where the resistor (R ₇ ) is The high resistance allows only the normal monitoring current to flow through the transistor Tr ₄ , and the resistance R ₆ is set to a value small enough that the thyristor SCR cannot conduct at the normal monitoring current level. Transistor Tr only during the operation of the switching circuit S The size of the thyristors (SCR) can be securely selected by the emitter current of ₄ ).

In this way, in the normal monitoring phase, the monitoring current of the detector flowing through the constant voltage circuit C is reduced by the high resistance of the resistor R ₇ , and during reception of the detector by the conduction of the thyristor SCR. Alternatively, as much current as necessary to reliably operate the relay relay can be distributed to the line.

In the above description, the DC voltage supplied from the receiver or the repeater to the detector has been sufficiently smoothed. However, since the DC power of the actual receiver is most of the pulsation voltage due to single phase full-wave rectification, etc., as shown in FIG. It becomes more practical if the braiding capacitor Co and the backflow blocking diode Di are connected to the line side of the constant voltage circuit C. FIG.

As described above, the fire detector having the constant voltage circuit according to the present invention can suppress the current flowing through itself in a normal monitoring state as much as possible by a simple structure, and at the same time, it can be used for receiving or There is an effect that can distribute the current required to the line to operate the relay relay reliably.

Claims (1)

A series transistor type constant voltage circuit is provided on the line side of the fire detector, and in this constant voltage circuit, the collector of the transistor is selected only at the time of operation of the detector while selecting a high resistance value in the circuit for supplying the base current of the transistor to be a control part. Or a fire detector having a constant voltage circuit for providing a circuit for amplifying the current flowing in the emitter and for distributing the operating current of the receiving or relay relay through the circuit.