CN2128099Y

CN2128099Y - Automatic temp. controlling circuit for electric rice cooker

Info

Publication number: CN2128099Y
Application number: CN 92225220
Authority: CN
Inventors: 李小雷
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-06-23
Filing date: 1992-06-23
Publication date: 1993-03-17
Anticipated expiration: 2002-06-23

Abstract

The utility model relates to the improvement of automatic temperature controlling circuits for household appliances and electric rice cookers. A set of electronic automatic temperature controlling circuits is additionally installed outside the triggering control circuits of a universal dual-direction static thyristor, and the electronic automatic temperature controlling circuits carry out automatic conversion according to the sequence processes of cooking and heat preservation and different requirements of temperature, so that the realization of the whole process of cooking can be ensured. After the improvement, the utility model carries out temperature control according to the different operating states of electronic circuits, a traditional mechanical magnetic steel temperature limiter is cancelled, complicated computer chips are not needed, and the manual controlling function of the original triggering circuits is not affected. The utility model plays the roles of multipurpose automatic and reliable operation.

Description

Automatic temp. controlling circuit for electric rice cooker

The present invention is to family expenses electric heater automatic temperature-adjusting control, particularly to the improvement of electric cooker automatic temperature-adjusting control technology.

The temperature of automatic electric rice cooker is main magnetic steel temperature limiter and the thermometal Huan temperature device of adopting of control automatically, when reaching magnet steel temperature Curie point, and just loss of excitation action of magnet steel, electric contact disconnecting consumers circuit is intermittently connected load by thermometal Huan temperature device then.Sort circuit, owing to be by the direct control load of mechanical force, electric contact directly bears the big electric current of load, thus very easily galvanic corrosion, and spring force and foreign matter factor affecting such as enter and also break down easily.

In order to address this problem, present high-grade electric cooker adopts the system controlled by computer controllable silicon to command whole pot meal process, but sort circuit cost height, and it is complicated that maintenance also is tending towards.

The objective of the invention is to provide a kind of improved electric cooker automatic temperature control circuit, it has not only exempted mechanical type temperature-adjusting circuit structure, and can carry out the automatic or manual step-less adjustment and select, automatic control circuit, the automatic realization of the meal process that can effectively guarantee to stew.

Invention is achieved in that on general bidirectional triode thyristor trigger circuit resistance adjustment arm, installed one group of electron temperature automaton additional with single-pole double-throw switch (SPDT), alternating current through rectifying and wave-filtering, supply with the circuit and of cooking with the direct current form based on the thermal circuit of one-way SCR and PTC element with one-way SCR and temperature-sensitive reed switch Guan Weizhu, the automatic mode of these two circuit again reverse influence to the alternating current path of rectifier bridge, it is the The Trigger of Bidirectional Triode Thyristor circuit, make the corresponding change of conducting state of bidirectional triode thyristor, thus the program of heating and the temperature of automatic control load.

The present invention is because only need install several electronic components additional on the basis of general bidirectional triode thyristor regulating circuit, so circuit is also uncomplicated, simultaneously because the starting point of invention does not lie in time-program(me) control, so it to the design complicated process of circuit and power supply power supply mode without any special requirement, what automatic temperature control circuit adopted in addition is the principle of work of electronic relay, stablize so trigger, realize the requirement of Program Synchronization easily.The concrete structure of invention is provided by following embodiment and accompanying drawing thereof.

Fig. 1 is the electrical schematic diagram of the electric cooker electronics automatic temp controller of proposition according to the present invention.

Describe the details and the working condition of the physical circuit that proposes according to the present invention in detail below in conjunction with Fig. 1.

This circuit comprises that with one-way SCR (1) temperature-sensitive reed switch pipe (4) be the main circuit of forming and serve as the main constant-temperature circuit of forming with one-way SCR (2) PTC element (5) of cooking, when single-pole double-throw switch (SPDT) (6) when being selected in automated location, the size of the interchange trigger current that rectifier bridge (3) passes through and having or not, depend on that fully the direct current outgoing side respectively organizes the duty of control element, single-pole double-throw switch (SPDT) among the figure (6) is in automatic working method.Press start button (7), one-way SCR (1) is conducting, this moment direct current through current-limiting resistance (13) (9) and one-way SCR (1) and temperature-sensitive reed switch pipe (4) to negative pole formation loop, this electric current is about is enough to make bidirectional triode thyristor (15) to be in fully conducting state about 25mA, electrothermal load (20) total head is heated, along with temperature rises, the thermistor of negative temperature coefficient (10) resistance descends, after surpassing 60 ℃, just to reach the low resistance that is enough to trigger one-way SCR (2), but the anode of one-way SCR this moment (1) is an electronegative potential, when the temperature of only cooking reaches 102 ± 0.5 ℃, temperature-sensitive reed switch pipe (4) disconnects one-way SCR (1), its anode voltage rises, just make the current trigger one-way SCR (2) by thermistor (10) and current-limiting resistance (21), direct current diverted via current-limiting resistance (11) one-way SCR (2) behind current-limiting resistance (13) and PTC element (5) to negative pole forms the loop.PTC element (5) is operated in about 70 ℃, and under its automatic control, thermal circuit pot meal of always working finishes.

Claims

1, a kind of automatic temperature control circuit that is used for electric cooker, be to constitute automatic temperature control circuit by the major loop of the major loop of the circuit one-way SCR (1) of cooking and the thermal circuit one-way SCR (2) in parallel with it at the direct current outgoing side of rectifier bridge (3), the negative electrode that it is characterized in that described one-way SCR (1) negative electrode of temperature-sensitive reed switch pipe (4) one-way SCR (2) the PTC element (5) of connecting of connecting.

2, according to the described automatic temperature control circuit of claim 1, the control utmost point that it is characterized in that one-way SCR (1) is serially connected with the adjustable current-limiting resistance of start button (7) (8), and its other end of thermistor (10) that is serially connected with negative temperature coefficient at the control utmost point of one-way SCR (2) is connected between current-limiting resistance (9) and one-way SCR (1) anode on the connecting line.

3, according to claim 1 or 2 described automatic temperature control circuits, it is characterized in that the Curie temperature of temperature-sensitive reed switch pipe (4) is selected in 102 ± 0.5 ℃, the Curie temperature of PTC element (5) is selected in 70--75 ℃.

4, according to claim 1 or 2 described automatic temperature control circuits, it is characterized in that being serially connected with electrolytic capacitor filter device (19) between rectifier bridge (3) the dc output end anticathode current-limiting resistance (13) of between the tapping point of the tapping point of electrolytic condenser (19) and anodal wiring and current-limiting resistance (11) and anodal wiring, connecting.

5, according to claim 1 or 4 described automatic temperature control circuits, it is characterized in that the end of ac input end of rectifier bridge (3) and three wiring tie points of electric capacity (16) potentiometer (17) and resistance (18) join, the other end of rectifier bridge (3) ac input end is connected to the stationary contact extension line of single-pole double-throw switch (SPDT) (6), corresponding another stationary contact extension line and resistance (14) join, and the extension line of moving contact directly is connected with load (20).