JPS5834557Y2 - battery operated smoke detector - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a battery-powered smoke detector.

As shown in Figure 1, a conventional battery-powered smoke detector includes a detection circuit 1 that detects smoke, an amplifier 2 that amplifies the detection signal of the detection circuit 1, and an alarm signal that processes the output signal of the amplifier 2. The sensor A that is connected to the output signal processing circuit 3 is connected to the battery 4 via the NC contact of the pull switch SW,
A series circuit consisting of a sounding element 5 consisting of a buzzer and a transistor 6 driven by the alarm output of the signal processing circuit 3 was connected to a battery 4 through an NC contact of a pull switch SW.

The operation of this conventional circuit is as shown in the figure: when an alarm signal is output from the signal processing circuit 3 and the transistor 6 is driven, the sound generating element 5 sounds to issue an N alarm.

Next, when the pull switch SW is pulled to open the NC contact as shown in Figure 2a, the battery 4 is disconnected and the alarm can be stopped as shown in Figure 2.

Now, when the cause of the alarm is removed and the pull switch SW is reset, the charging current flows through the series circuit of the capacitor 7 and the resistor 8 connected between the battery 4 side end of the sound generating element 5 and the base of the transistor 6, causing an instantaneous transistor. 6 is turned on and the sound generating element 5 is made to sound 11 as shown in FIG. 2C to notify that the battery 4 is normal.

By the way, the general psychology of humans is to expect a change when the pull switch SW is suddenly operated, but as mentioned above, when the sound generating element 5 emits the notification sound at the time of return, it is handled as causing an instantaneous surprise. There was a problem.

The present invention was developed in view of this problem, and its purpose is that when the pull switch is suddenly operated during normal operation, if the battery is normal, the sounding element will ring for a moment to notify you, and when the pull switch is activated during an alarm. The purpose is to provide a battery-operated sensor that can turn off the alarm when operated casually.

The present invention will be explained below by way of an example.

FIG. 3 shows a circuit diagram of one embodiment.

In this embodiment circuit, a series circuit consisting of a sound generating element 5 consisting of a buzzer and a transistor 6 is connected in parallel to a battery 4, and a sensing section A having the same configuration as the conventional example in FIG. 1 is connected to a common terminal of a pull switch SW. , connect to the battery 4 via the NC contact and resistor R1, further connect the base of the transistor 6 to the NO contact of the pull switch SW via the resistor R2, and connect the capacitor 9 in parallel to the sensing part A. be.

In normal times, the pull switch SW is set to the state shown in the figure.

When all the sensing parts A are activated and the transistor 6 is driven, a driving current flows through the sounding element 5, which is like a buzzer, and the sounding element 5 sounds and generates a t-signal.

If the pull switch SW is suddenly operated as shown in FIG. 4a, the power to the sensing section A is cut off, and the alarm stops as shown in FIG. 4 after the capacitor 9 is discharged.

Now, if it is desired to check the battery 4 under normal conditions, the pull switch SW is suddenly operated as shown in FIG. 4a.

That is, when the pull switch swIJzNc contact is switched to the NO contact, the charge stored in the capacitor 9 is discharged through the common terminal of the pull switch SW, the NO contact, the resistor R2, and the base of the transistor 60. Instantly turns on.

As a result, the sound generating element 5 sounds for a moment as shown in FIG. 4C to notify that the battery 4 is normal.

When the pull switch SW is reset, the circuit returns to the normal alert state and the capacitor 9 is charged.

As long as the capacitor 9 has a capacity sufficient to drive the sound generating element 5, the power supply side end of the sound generating element 5 may of course be connected to the common terminal of the pull switch SW.

FIG. 5 shows another embodiment circuit of the present invention. This embodiment uses a single-pole, single-throw pull switch SW, and connects the sensing part A and the capacitor through the NC contact of the pull switch SW. 9 is connected to the battery 4, a series circuit of the sound generating element 5 and the transistor 6 is connected to the battery 4, and the emitter/base of the transistor 10 and the resistor 1 are connected in parallel to the pull switch SW.
1 and a capacitor 12 are connected in series, a diode 13 is connected between the emitter and the base of the transistor 10, and the collector of the transistor 10 is connected to the base of the transistor 60 via a resistor R2 to form a circuit.

The alarm can be stopped by opening the NC contact of the pull switch SW in the same manner as described above.

In addition, when checking the battery 4, if the NC contact of the pull switch SW is opened, the resistor 11 and capacitor 1
A base current flows to the base of the transistor 10 through the transistor 2 and turns it on, so that the collector current of the transistor 10 flows through the diode 13, and this collector current flows to the base of the transistor 60 through the resistor R2.

As a result, the transistor 6 is turned on and the sound generating element 5 is made to sound.

The charging of the capacitor 12 is completed in about several tens of m5ec, and when the charging current becomes zero, the transistor 6 is turned off and the sounding of the sound generating element 5 ends in an instant.

When the NC contact of the pull switch SW is returned to its original state, the charge on the capacitor 12 is transferred to the capacitor 12, the resistor 11, the diode 13, the NC contact of the pull switch SW,
The capacitor 12 is discharged in the closed circuit, and the next pull switch S
Waits for W operation.

By the way, when the capacity of the battery 4 decreases, the capacitor 12 is in a charged state, and even if the pull switch SW is operated, the transistor 10 does not operate, and the sound generating element 5 does not vibrate.

FIG. 6 shows a circuit diagram of another embodiment of the present invention, in which the signal processing circuit 3 of the sensing section A and the capacitor 9 are connected to the battery 4 through the NC contact of the pull switch SW and the diode 14. The base and emitter of the transistor 150 are connected to both ends of the diode 140, and the transistor 1
5 is connected to the base of a transistor 60 via a resistor R2.

However, if the battery 4 is in a normal state and the full switch SW is
When the contacts are opened, the charge on capacitor 9 is discharged through the emitter and base of transistor 15, turning transistor 15 on.

The collector current of this transistor 15 is
0 base, and transistor 6 is turned on.

As a result, the sound generating element 5 is made to sound until the capacitor 9 is no longer charged.

Although the amplifier 2 of the sensing section A is used in the discharge path of the capacitor 9, other circuits or resistors may be used.

Note that if this discharge resistance is too small, the capacity of the battery 4 will decrease when the pull switch SW is opened.

The present invention is configured as described above, and the pull switch is
A base current circuit is added to the base of the transistor that uses the discharging or charging of the capacitor to flow current when the contact is opened, so when the NC contact of the pull switch is opened, the transistor is momentarily turned on and the sound generating element is momentarily turned on. It has the advantage that the battery can be checked when the pull switch is operated, and there is no operational disadvantage such as the sounding element ringing at unexpected times such as when the pull switch is reset. Moreover, the alarm can be stopped in the same way as before.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram of a conventional example, Figure 2 is an explanatory diagram of the same operation as above,
Figure 3 is a circuit diagram of one embodiment of the present invention, Figure 4 is an explanatory diagram of the same operation as above, Figure 5 is a circuit diagram of another embodiment of the present invention, and Figure 6 is a circuit diagram of another embodiment of the present invention.
The figure is a circuit diagram of another embodiment of the present invention, where A is a sensing section;
SW is a pull switch, 4 is a battery, 5 is a sounding element, 6 is a transistor, and 9°12 is a capacitor.

Claims (1)

[Scope of utility model registration request] A series circuit consisting of a sounding element such as a buzzer and a transistor is connected to the battery, and a sensing part is connected to the battery via the NC contact of a pull switch, and when the NC contact of the pull switch is opened, a capacitor is connected to the base of the transistor. A battery-powered smoke detector that includes a base current circuit that instantaneously flows a base current using the discharging or charging of the battery.