Temperature alarm circuit

Abstract

The utility model discloses a temperature alarm circuit, which comprises a temperature sensor, a controller and an alarm, the temperature sensor is electrically connected with the controller, the alarm comprises a first resistor, a first capacitor, a first triode and a loudspeaker, the first end of the first resistor is electrically connected with the controller, and the second end of the first resistor is electrically connected with the controller. The second end of the first resistor is electrically connected with the base electrode of the first triode; the first end of the first capacitor is electrically connected with the second end of the first resistor, and the second end of the first capacitor is grounded; the collector electrode of the first triode is used for being electrically connected with a power supply, the emitter electrode of the first triode is electrically connected with the positive electrode connecting end of the loudspeaker, and the negative electrode connecting end of the loudspeaker is grounded. The utility model has the advantages of strong anti-interference capability, simple structure and low cost.

Description

Technical Field

[0001] The utility model relates to the technical field of high temperature alarm, in particular to a temperature alarm circuit. Background Art

[0002] With the development of science and technology, the alarm industry has also developed rapidly. There is a great demand in the defense and civilian industries. The requirements for its accuracy and quality are constantly increasing. Pressure, anti-theft, temperature, humidity and other alarms can be seen everywhere during use. For example, with the rapid development of the IT industry, the integration of computers has gradually increased, and the computing speed has been continuously improved. The heat dissipation of heat-generating components has become the key to affecting the service life of computers.

[0003] Among them, CPU heat dissipation is affected by the temperature change inside the computer case. After the computer has been working for a period of time, the temperature inside the case rises, and the computer's heat dissipation capacity decreases. The decrease in heat dissipation capacity causes the temperature inside the computer case to rise, and the temperature increase affects the network speed, which in turn affects people's normal work; excessive temperature may also cause the computer CPU to burn out. For this reason, a temperature alarm circuit for warning high temperature came into being. However, the existing temperature alarm circuit has a complex structure and high cost. Utility Model Content

[0004] The technical problem solved by the utility model is to provide a temperature alarm circuit with simple structure and low cost.

[0005] The utility model provides a temperature alarm circuit, comprising a temperature sensor, a controller and an alarm, wherein the temperature sensor is electrically connected to the controller, and the alarm comprises a first resistor, a first capacitor, a first transistor and a speaker, wherein the first end of the first resistor is electrically connected to the controller, and the second end of the first resistor is electrically connected to the base of the first transistor; the first end of the first capacitor is electrically connected to the second end of the first resistor, and the second end of the first capacitor is grounded; the collector of the first transistor is used to be electrically connected to a power supply, the emitter of the first transistor is electrically connected to the positive connection end of the speaker, and the negative connection end of the speaker is grounded.

[0006] Preferably, the temperature alarm circuit also includes a second transistor, the base of the second transistor is electrically connected to the controller, the collector of the second transistor is electrically connected to the collector of the first transistor, and the emitter of the second transistor is electrically connected to the positive connection terminal of the speaker.

[0007] Preferably, the temperature alarm circuit also includes a second resistor, a first end of the second resistor is electrically connected to the collector of the first transistor, a second end of the second resistor is used to be electrically connected to the power supply, and the collector of the first transistor is electrically connected to the power supply through the second resistor.

[0008] Preferably, the collector of the second transistor is electrically connected to the power supply through the second resistor.

[0009] Preferably, the temperature alarm circuit further includes a second capacitor, a first end of the second capacitor is electrically connected to the base of the second transistor, and a second end of the second capacitor is grounded.

[0010] Preferably, the temperature alarm circuit also includes a third resistor, a first end of the third resistor is electrically connected to the controller, and a second end of the third resistor is electrically connected to the base of the second transistor; the base of the second transistor is electrically connected to the controller through the third resistor.

[0011] Preferably, the temperature sensor includes a third transistor, the base of the third transistor is electrically connected to the controller, the collector of the third transistor is electrically connected to the base of the fourth transistor, and the emitter of the fourth transistor is electrically connected to the controller.

[0012] Preferably, the temperature sensor further comprises a third capacitor, a first end of the third capacitor is electrically connected to the base of the third transistor, and a second end of the third capacitor is electrically connected to the emitter of the third transistor.

[0013] The utility model has the following beneficial effects: the utility model cooperates with a temperature sensor, a controller and an alarm, wherein the temperature sensor is electrically connected to the controller, and the alarm includes a first resistor, a first capacitor, a first transistor and a speaker, wherein the first end of the first resistor is electrically connected to the controller, and the second end of the first resistor is electrically connected to the base of the first transistor; the collector of the first transistor is used to be electrically connected to a power supply, the emitter of the first transistor is electrically connected to the positive connection end of the speaker, and the negative connection end of the speaker is grounded. Therefore, when the temperature detected by the temperature sensor is greater than a preset value, the controller controls the first transistor to turn on, thereby driving the speaker to sound and send out an alarm signal. The circuit has the advantages of simple structure and low cost. In addition, filtering is performed through the first capacitor, thereby better avoiding false alarms and having strong anti-interference ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The utility model is a functional block diagram of the temperature alarm circuit.

[0015] Figure 2 The utility model is a circuit diagram of an alarm device of a temperature alarm circuit.

[0016] Figure 3 The utility model is a circuit diagram of a temperature sensor of a temperature alarm circuit. DETAILED DESCRIPTION

[0017] The present invention is described in detail below in conjunction with the accompanying drawings and embodiments. It should be noted that, if there is no conflict, the embodiments of the present invention and the various features in the embodiments can be combined with each other, all within the protection scope of the present invention.

[0018] See also Figures 1 to 3 The utility model provides a temperature alarm circuit, including a temperature sensor 1, a controller 2 and an alarm 3. The temperature sensor 1 is electrically connected to the controller 2. The alarm 3 includes a first resistor R1, a first capacitor C1, a first transistor Q1 and a speaker P. The first end of the first resistor R1 is electrically connected to the controller 2, and the second end of the first resistor R1 is electrically connected to the base of the first transistor Q1; the first end of the first capacitor C1 is electrically connected to the second end of the first resistor R1, and the second end of the first capacitor C1 is grounded. The collector of the first transistor Q1 is used to be electrically connected to a power supply, the emitter of the first transistor Q1 is electrically connected to the positive connection end of the speaker P, and the negative connection end of the speaker P is grounded.

[0019] The temperature alarm circuit further includes a second transistor Q2, the base of the second transistor Q2 is electrically connected to the controller 2, the collector of the second transistor Q2 is electrically connected to the collector of the first transistor Q1, and the emitter of the second transistor Q2 is electrically connected to the positive connection end of the speaker P. Therefore, by controlling the on and off of the second transistor Q2, the speaker P can be controlled to emit different sound signals.

[0020] The temperature alarm circuit further includes a second resistor R2, a first end of the second resistor R2 is electrically connected to the collector of the first transistor Q1, a second end of the second resistor R2 is used to be electrically connected to the power supply, and the collector of the first transistor Q1 is electrically connected to the power supply through the second resistor R2. The collector of the second transistor Q2 is electrically connected to the power supply through the second resistor R2. The second resistor R2 can achieve the functions of voltage reduction and current limiting.

[0021] The temperature alarm circuit further includes a second capacitor C2 and a third resistor R3, wherein the first end of the second capacitor C2 is electrically connected to the base of the second transistor Q2, and the second end of the second capacitor C2 is grounded. The first end of the third resistor R3 is electrically connected to the controller 2, and the second end of the third resistor R3 is electrically connected to the base of the second transistor Q2; the base of the second transistor Q2 is electrically connected to the controller 2 via the third resistor R3.

[0022] The temperature sensor 1 includes a third transistor Q3 , the base of the third transistor Q3 is electrically connected to the controller 2 , the collector of the third transistor Q3 is electrically connected to the base of the fourth transistor, and the emitter of the fourth transistor is electrically connected to the controller 2 .

[0023] The temperature sensor 1 further comprises a third capacitor C3, a first end of the third capacitor C3 is electrically connected to the base of the third transistor Q3, and a second end of the third capacitor C3 is electrically connected to the emitter of the third transistor Q3. The temperature sensor 1 has the advantages of simple structure and stable signal.

[0024] In summary, the utility model cooperates with the temperature sensor 1, the controller 2 and the alarm 3. The temperature sensor 1 is electrically connected to the controller 2. The alarm 3 includes a first resistor R1, a first capacitor C1, a first transistor Q1 and a speaker P. The first end of the first resistor R1 is electrically connected to the controller 2, and the second end of the first resistor R1 is electrically connected to the base of the first transistor Q1. The collector of the first transistor Q1 is used to be electrically connected to a power supply, the emitter of the first transistor Q1 is electrically connected to the positive connection end of the speaker P, and the negative connection end of the speaker P is grounded. Therefore, when the temperature detected by the temperature sensor 1 is greater than a preset value, the controller 2 controls the first transistor Q1 to turn on, thereby driving the speaker P to sound and send out an alarm signal. The circuit has the advantages of simple structure and low cost. In addition, filtering is performed by the first capacitor C1, so that false alarms can be better avoided.

[0025] The temperature alarm circuit provided by the utility model is introduced in detail above. The principle and implementation mode of the utility model are explained in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the utility model. At the same time, for those of ordinary skill in the art, according to the idea of ​​the utility model, there will be changes in the specific implementation mode and application scope. In summary, the content of this specification is only the implementation mode of the utility model, and it does not limit the patent scope of the utility model. All equivalent structures or equivalent process changes made by using the contents of the specification and drawings of the utility model, or directly or indirectly used in other related technical fields, are included in the patent protection scope of the utility model and should not be understood as limitations on the utility model.

Claims

1. A temperature alarm circuit, characterized in that: It includes a temperature sensor, a controller and an alarm, the temperature sensor is electrically connected to the controller, the alarm includes a first resistor, a first capacitor, a first transistor and a speaker, the first end of the first resistor is electrically connected to the controller, the second end of the first resistor is electrically connected to the base of the first transistor; the first end of the first capacitor is electrically connected to the second end of the first resistor, and the second end of the first capacitor is grounded; the collector of the first transistor is used to be electrically connected to a power supply, the emitter of the first transistor is electrically connected to the positive connection end of the speaker, and the negative connection end of the speaker is grounded.

2. The temperature alarm circuit according to claim 1, characterized in that: The temperature alarm circuit also includes a second transistor, the base of the second transistor is electrically connected to the controller, the collector of the second transistor is electrically connected to the collector of the first transistor, and the emitter of the second transistor is electrically connected to the positive connection terminal of the speaker.

3. The temperature alarm circuit according to claim 2, characterized in that: The temperature alarm circuit also includes a second resistor, a first end of the second resistor is electrically connected to the collector of the first transistor, a second end of the second resistor is used to be electrically connected to the power supply, and the collector of the first transistor is electrically connected to the power supply through the second resistor.

4. The temperature alarm circuit according to claim 3, characterized in that: The collector of the second transistor is electrically connected to the power supply through the second resistor.

5. The temperature alarm circuit according to claim 3, characterized in that: The temperature alarm circuit further includes a second capacitor, a first end of the second capacitor is electrically connected to the base of the second transistor, and a second end of the second capacitor is grounded.

6. The temperature alarm circuit according to claim 3, characterized in that: The temperature alarm circuit also includes a third resistor, a first end of the third resistor is electrically connected to the controller, and a second end of the third resistor is electrically connected to the base of the second transistor; the base of the second transistor is electrically connected to the controller through the third resistor.

7. The temperature alarm circuit according to claim 1, characterized in that: The temperature sensor includes a third transistor, the base of the third transistor is electrically connected to the controller, the collector of the third transistor is electrically connected to the base of the third transistor, and the emitter of the third transistor is electrically connected to the controller.

8. The temperature alarm circuit according to claim 7, characterized in that: The temperature sensor further includes a third capacitor, a first end of the third capacitor is electrically connected to the base of the third transistor, and a second end of the third capacitor is electrically connected to the emitter of the third transistor.

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