76 results about "555 timer IC" patented technology

The invention relates to a digital control device and method for an LLC (logical link control) synchronously-rectified resonant converter. The device comprises a digital signal processor, a primary high-frequency driving circuit, a current sampling detection circuit, a voltage sampling detection circuit and a secondary high-frequency driving circuit, wherein the digital signal processor judges an operation area of a circuit according to an output voltage fed back by the voltage sampling detection circuit, after the circuit performs three-pole two-zero compensation, the values of an on-chip period register are respectively changed so as to generate high-frequency driving signals which are then output to the primary and secondary high-frequency driving circuits by the digital signal processor; the current sampling detection circuit detects a secondary output current which is then output to the digital signal processor, then the digital signal processor judges whether an overloading or overcurrent phenomenon (generated in the process of area switching) occurs according to the size of the current so as to cut off the primary and secondary high-frequency driving circuits in time. In the invention, the LLC resonant converter is subjected to the following digital control by a digital signal processing chip-peripheral timer combined circuit: the advanced conduction of secondary synchronous rectifying tubes is realized by the design of software / hardware auxiliary circuits, and the control on secondary driving signals is performed by adding a 555 timer, so the application of a timer in a DSP (digital signal processing) chip is reduced, thereby effectively solving the problem of conduction loss of synchronous rectifying tubes introduced in the process of underloading in the traditional control strategy; and the application of a PWM (pulse-width modulation) port of the digital signal processing chip is reduced, thereby improving the reliability of the whole device.

The invention belongs to the technical field of switch control, and discloses a control device of an electromagnetic brake. The control device comprises a main circuit, a control circuit and a protection circuit. According to the invention, an IGBT (insulated gate bipolar translator) conduction angle is controlled by adopting two monostable triggers formed by two 555 timers via the logic relation conversion of a logic gate circuit, so as to further control the voltage at two ends of the coil of the electromagnetic brake. The control device comprises a zero passage trigger circuit having a feedforward action, and when the input voltage of the control device changes, the zero passage trigger circuit can stabilize the voltage at two ends of an electromagnetic coil via the adjustment of the feedforward link. The control device also comprises an efficient and rapid discharge circuit which can rapidly release energy in the coil of an electromagnet after outage, and also has the protection measures of low voltage protection, short circuit protection, open circuit protection and the like, so that the electromagnetic brake is safer and more stable and reliable in operation.

The invention relates to an energy-saving electricity getting and door closing reminder, in particular to a dormitory electricity getting and door closing reminder which can prevent householders from carelessly wasting electric energy and using the electric energy by stealing. The reminder comprises a reflective optoelectronic coupler, a 555 timer, a relay control circuit, a alternating voltage control circuit, a timing and alarming integrated circuit, a door magnistor and the like. The invention is an electronic device reminder which is suitable for being assembled and used in a dormitory and is composed of the 555 timer, the door magnistor, the optoelectronic coupler and the alarming device. When users come back to the dormitory, the electricity can be used only by inserting a card; and when the users leave the dormitory, the power supply can be cut off, and a reminding alarm can be given out in time if the door is not closed.

The invention discloses a fan control circuit with functions of controlling the temperature and preventing touch and electric leakage. The fan control circuit comprises a voltage stabilizing tube VD1, a heat-sensitive resistor Rt, a 555 timer IC1 and a two-way thyristor VS1. The fan is characterized in that a pin 1 of the 555 timer IC1 is connected to one end of a capacitor C2, a pin 4 and a pin 8 of the 555 timer IC1 are connected to the other end of the capacitor C2 simultaneously; the low triggering end of the 555 timer IC1 is connected to the connecting position of a resistor R2 and a resistor R3, the high triggering end of the 555 timer IC1 is connected to the connecting position of the heat-sensitive resistor and a resistor R3, the discharging end of the 555 timer IC1 is connected between the resistor R3 and the resistor R2 by a resistor R4, and the output end of the 555 timer IC1 is connected with the control electrode of the two-way thyristor VS1 by a resistor R4. The fan control circuit disclosed by the invention has the advantages that the starting and the stopping of a fan can be controlled according to the external temperature, so that not only the comfort is ensured, but also the electric energy is saved; the fan control circuit also has the functions of preventing from touching fan blades and protecting from electric leakage, the beneficial effect is obvious, and the application and the promotion are convenient.

The invention discloses a household electric appliance electric leakage protection socket comprising a power supply jack and an electric leakage protector which is connected with the power supply jack. The electric leakage protector comprises an electric leakage detection module, an electric outage execution module and a power supply module which supplies DC power supply VCC to the electric outage execution module. The electric leakage detection module is composed of a rectifier diode, a first current-limiting resistor and an optoelectronic coupler. The electric outage execution module comprises a trigger circuit, an execution circuit and an alarm circuit. The trigger circuit is composed of a 555 timer, a pull-up resistor, a timing resistor, a timing capacitor and an anti-interference capacitor. The execution circuit is composed of a coil of a relay, a normally-closed contact point of the relay and a freewheeling diode. The alarm circuit is composed of a second current-limiting resistor, a triode, a loudspeaker, a third current-limiting resistor and a red light-emitting diode. When electric leakage occurs in household electric appliances, the socket can generate acousto-optic alarm and cut off power so that the socket is simple in circuit structure, high in reliability of electric leakage protection, long in the service life and low in manufacturing cost.

The invention relates to a piezoelectric material parameter test method and a test apparatus based on a dynamic method. A to-be-tested piezoelectric material is connected with a standard resistor in series, an impedance-frequency spectrum of the to-be-tested piezoelectric material is obtained through frequency sweep, a series connection resonant frequency fs and a parallel connection resonant frequency fp of the piezoelectric material can be calculated by change of corresponding impedance amplitudes, and the impedance value corresponding to the series connection resonant frequency is a dynamic resistance value Res of the to-be-tested piezoelectric material. A free capacitance value of the to-be-tested piezoelectric material is converted to a frequency value with a function relation by employing a 555 timer circuit, a corresponding static capacitance Cap is obtained through calculation, and the mechanical quality factor Qm can be calculated with the combination of the above four parameters.

The invention discloses a high-voltage pulse power supply controlled by a 555 timer. Positive electrodes of a high-voltage direct current power supply are connected with 64 insulated gate bipolar transistor (IGBT) circuits in series connection. The 64 IGBT circuits which are in series connection are connected with one ends of loads. The other ends of the loads are connected to negative electrodes of the high-voltage direct current power supply. Pulse signals output by circuits of the 555 timer are connected with 16 IGBT drive circuits after passing through a pulse-width modulation (PWM) amplifying circuit. Each IGBT drive circuit drives 4 IGBTs which are in series connection. The 16 IGBT drive circuits are connected with output ends of the circuits of the 555 timer after passing through 64 fault detection circuits and fault feedback circuits. By utilizing pulse signals output by the circuits of the 555 timer to control on-off of the IGBTs, about 40kV high-voltage pulses adjustable in both frequency and duty ratio can be output.

The invention relates to a traffic warning fog-proof lamp used in toll islands or both sides of fog sections along freeways to provide sight induction for drivers in foggy or abnormal weather. The invention comprises a time control circuit as a core component, a rectifier circuit which provides a direct current power supply for the time control circuit, a display circuit which receives output signals of the time control circuit and a photosensitive resistance control circuit; wherein, the output of the photosensitive resistance control circuit is connected with the time control circuit to control the opening and closing of a timer and the stroboscopic speed of the display circuit; the photosensitive resistance control circuit comprises a multi-vibrator and a stroboscopic control circuit; the display circuit consists of ultra bright blue light emitting diodes connected in a parallel and serial way; a 555 timer is adopted as the time control circuit. The invention is used for automatically turning off or turning on the traffic warning fog-proof lamp and providing sight induction for drivers according to visibility degree. The lamp has a simple structure, is practical and plays a good role of energy saving.

The invention discloses a DC stabilized voltage power supply switch control device, which comprises a hand switch which is a normally open type key switch for manual switch control; a control signal input terminal which is used for inputting automatic switch control signal; a 555 timer which has TH and / TL pins connected with the hand switch, a / RES pin connected with the control signal input terminal, and an OUT pin connected with a clock pin of a D trigger; the D trigger which has a D pin directly connected with a / Q pin, a Q pin and / or the / Q pin connected with a power supply control unit for outputting a switch control signal; and the power supply control unit which is used for carrying out switch control according to the switch control signal from the D trigger. The stabilized voltage power supply control device can be controlled through an external signal or manually through the normally open type key switch and has simple circuit, good stability and high reliability.

The invention discloses a water-level alarm device, belonging to the technical field of liquid level monitoring. The water-level alarm device comprises two detection electrodes put in water, a detection circuit connected with the detection electrodes, and a loudspeaker Y connected with the detection circuit, wherein the detection circuit is a multivibrator composed of a 555 timer and a plurality of capacitors and resistors; one detection electrode is connected with pins 2 and 6 of the 555 timer, and the other electrode is connected to the ground through the capacitor C1; the loudspeaker Y is connected between pins 3 and 8 of the 555 timer in parallel; and a pin 7 of the 555 timer is connected with a power source through the resistor R1, and connected with the ground through the resistor R2. The invention has the advantage of safe and simple circuit design, and can automatically sound the alarm when the liquid level reaches the alarm position.

A multi-touch piezoelectric warning circuit comprises an energy storage circuit and an alarm circuit. The multi-touch piezoelectric warning circuit adopts three triggering modes, the first mode is that a produced current fluctuation signal is transferred to a 555 timer chip to give an alarm when a piezoelectric sensor produces vibration, the second mode is that the produced fluctuation signal is transferred to a 555 timer chip to give an alarm when an electrode plate produces vibration, the third mode is that a TR interface of the 555 timer chip is connected with a grounding wire to produce low level and give an alarm when a vibration sensor produces vibration. Energy used by the multi-touch piezoelectric warning circuit is produced through the piezoelectric sensor and stored for utilization, and the piezoelectric sensor is a multi-layer composite plate or a beam structure and comprises a piezoelectric layer and a metal base layer. The multi-touch piezoelectric warning circuit is high in sensitivity and reliability, uses self-generated electricity energy and does not need battery replacement or external charging and other operations.

The invention relates to the field of automobile lamps, in particular to an automobile dynamic steering lamp system. When a vehicle turns, an input filter circuit is used for filtering out an alternating-current part in a power supply, and supplying the stable direct current to a linear voltage stabilizer and an LED driver for power supply; the linear voltage stabilizer is used for providing the stable working voltage for a 555 timer and a shifting register correspondingly; the 555 timer is used for generating a time delay signal of dynamic interval lighting of a dynamic steering lamp LED, andtransmitting the time delay signal to the shifting register; the shifting register is used for processing the time delay signal to obtain a shifting control signal, and transmitting the shifting control signal to the LED driver; and the LED driver is used for driving LED lamps in the dynamic steering lamp LED to be turned on in sequence. The LED progressively flickers from inside to outside to form a running type progressive flickering visual effect, so that when the vehicle turns, the attention of the vehicles and the pedestrians all around can be attracted to the greater extent, and the purpose of reminding is achieved.

The invention belongs to the field of medical disinfection, and discloses an ultraviolet disinfecting system for an operating room. The ultraviolet disinfecting system comprises an information acquisition unit, an information processing unit, an implementing unit, a timed starting unit and a power supply unit, wherein the information acquisition unit comprises a nano biosensor and a human body proximity sensor; the information acquisition unit is connected to the information processing unit; the information processing unit comprises a single chip controller which is connected to the information acquisition unit, a display screen which is connected to the single chip controller and a Flash memory; the implementing unit comprises an ultraviolet lamp, a camera, a voice broadcast device and an electromagnetic lock; the implementing unit and the single chip controller are connected; the timed starting unit comprises a 555 timer which is connected to the power supply unit and a touch switch which is connected to the 555 timer; and the power supply unit is electrically connected to the information acquisition unit, the information processing unit and the implementing unit by virtue of the timed starting unit. With the application of the ultraviolet disinfecting system provided by the invention, the environment of the operating room can be monitored in real time and comprehensive and effective disinfection can be automatically conducted, so that the labor intensity of cleaning personnel is reduced.

An electric bicycle charging device comprises a charger control module, a software module and a communication module, wherein the communication module is used for transmitting command information. Oneend of the charger control module is connected with the communication module through a lead, the other end of the charger control module is connected with a detection module, the communication moduleis connected with a charging control module, and the charging control module is connected with a timing module and the detection module. The charging control module comprises a single chip microcomputer which is used for controlling whether a charging power supply of an electric bicycle is powered on or not. The detection module comprises a voltage comparison chip which is used for comparing a set voltage value with a current battery voltage value. The timing module is provided with a 555 timer which is used when timing charging is performed. The software module is provided with a mobile phone APP (application) matched with the charging device, and the mobile phone APP is sued for helping the single chip microcomputer to judge and control. The communication module is provided with a Zigbee communication module, and a CC2430 chip is mounted in the Zigbee communication module.

The invention discloses a high-power LED constant current driving circuit and a parameter algorithm thereof. The constant current driving circuit comprises a 555 timer, an IR2125 driver, a voltage amplifier and a sampling resistor, the sampling resistor is connected with an LED string circuit, the IR2125 driver is connected with the LED string circuit through a driving VT switch, the voltage amplifier is connected with the sampling resistor and the 555 timer, and the 555 timer is connected with the IR2125 driver. A control signal outputted by the 555 timer drives a field effect transistor to be on or off through the IR2125 driver, and the current value of an LED string is adjusted. The hardware cost of the high-power LED electric light source driving circuit can be effectively reduced. As the control current of the driving circuit can be adjusted, the driving circuit is suitable for constant current driving of high-power LED (strings) within various power ranges. The driving circuit is simple in structure, high in control precision, low in cost and wide in applicable range.

The invention relates to a voltage-adjustable speed-adjustable controller of single-phase asynchronous motor. Wherein, said controller is formed by dial code setter, voltage-variable rectifying circuit, power zero detecting circuit, controllable silicon connection angle adjustable circuit, and controllable silicon driving circuit; said controller can based on the need of device adjust the voltage of motor to adjust the rotation speed of fan. The invention adjusts the trigger time of 555 timers to adjust the connecting angle of controllable silicon, and uses theory of chopped wave circuit to adjust the driving voltage of fan, to adjust the wind speed, to realize stepless speed adjustment. The invention has the advantages that it can stepless adjust the speed of fan, to reduce the noise and cost of indoor machine of air conditioner.

The invention discloses an infrared remote control lamp comprising an infrared emitter, an infrared receiver, an actuator and a bulb. The infrared emitter comprises a button, a battery, an adjustable resistor, a first resistor, a first capacitor, a 555 timer, a second capacitor, a second resistor and first and second infrared light-emitting diodes. The actuator adopts a bidirectional silicon controlled rectifier. The infrared receiver comprises an infrared receiving head with a model number of SFH506-38, a double-D trigger with the model number of SN74LS74, a fourth resistor and a voltage-reducing rectification filter circuit. The remote control lamp is simple in remote control circuit structure and low in cost so that the remote control lamp can be applied to occasions like households, offices or factories with server environment, and thus operation of turning on / off the lamp can be facilitated for people.

The invention discloses a control circuit and a control method for a brake circuit. The control circuit comprises a comparator circuit connected with a direct-current bus and used for comparing the voltage of the direct-current bus with a threshold voltage; a 555 timer circuit connected with the comparator circuit and used for outputting a voltage square wave signal when the voltage of the direct-current bus is larger than the threshold voltage; a push-pull circuit connected with the 555 timer circuit and used for controlling the turn-on state and the turn-off state of a brake tube IGBT according to the voltage square wave signal; and a brake circuit provided with the above brake tube IGBT and a brake resistor. According to the invention, the brake resistor is used for discharging to reduce the voltage of the direct-current bus when the brake pipe IGBT is conducted. Therefore, the technical problem in the prior art that CPU resources are occupied when the voltage of the direct-currentbus is reduced through a CPU is solved.

The invention provides a circuit control device and a vibrator based on muscle vibration. Wherein, the circuit control device includes: a multivibrator, the multivibrator includes a frequency adjustment switch, based on the 555 timer circuit, the frequency adjustment is realized by changing the resistance value of a plurality of resistors, and is used to adjust the above-mentioned multivibrator Transducers are capable of operating at several different frequencies. The invention solves the problem that the working frequency of the equipment used for muscle vibration training in the related art is relatively single and cannot adapt to the training needs of different parts, improves the practicability of vibration training, and can effectively meet the needs of skeletal muscles caused by long-term braking such as paralysis. Prevention of atrophy and skeletal muscle loss in aging.

This invention discloses a voice signal generator capable of adjusting pulse waveforms. A VCC pin of a 555 timer is simultaneously connected with a power supply and one end of an adjustable resistor R1; the other end of the adjustable resistor R1 is connected with a discharge end of the 555 timer and a sliding end of a potentiometer R2; one end of a fixed end of the potentiometer R2 is connected with a positive pole of a diode D1; a negative pole of the diode D1 is connected with one end of a resistor R7; the other end of the fixed end of the potentiometer R2 is connected with a negative pole of a diode D2; the positive pole of the diode D2 is connected with one end of a resistor R5; the other end of the resistor R5 is simultaneously connected with the other end of the resistor R7 and a frequency-modulation parallel circuit; the frequency-modulation parallel circuit is simultaneously connected with a threshold end and a trigger end of the 555 timer; the output end of the 555 timer is connected with one end of a resistor R3; the other end of the resistor R3 is connected with an inverting input end of an operational amplifier; an adjustable resistor R4 has a series connection between the output end and the inverting input end of the operational amplifier. Thus, the frequency, the duty ratio and the amplitude of the output voltage can be adjusted separately, and only one of the frequency, the duty ratio and the amplitude is changed without affecting the others.

The invention discloses a lamp and a power switch control circuit. The power switch control circuit comprises a 555 timer, a switch module, a switching tube, and an AC power supply. The switch module comprises a turning-on metallic sheet and a turning-off metallic sheet which are used for being touched by a user. The setting end of the 555 timer is connected with the turning-on metallic sheet while the resetting end of the 555 timer is connected with the turning-off metallic sheet. The output end of the 555 timer is connected with the control end of the switching tube. The first end of the switching tube is connected with the first end of a load. The second end of the load and the second end of the switching tube are connected with the two ends of the AC power supply, respectively. When the technical scheme of the invention is executed, the power switch control circuit achieves large current control with a small signal because a conventional mechanical switch is replaced by a touch switch. Therefore, faults caused by a fact that large current passes through the mechanical switch when the mechanical switch performs switch operation can be prevented.

The invention provides a generating circuit of pulse width modulation (PWM) signals. The generating circuit comprises a PWM oscillator circuit, wherein the PWM oscillator circuit further comprises a 555 timer, a first resistor, a second resistor, a third resistor and a capacitor element; the 555 timer is provided with a plurality of pins; each pin comprises an analog signal input end, a modulating signal input end and an output signal output end; and the three resistors and the capacitor element are all externally connected with the 555 timer. A detecting method of the PWM signals generated by the generating circuit is characterized by adopting a low-pass filter or an envelope detection method to demodulate the signals. The invention has the following beneficial effects: by adopting the 555 timer to form the generating circuit of the PWM signals, not only the method is simple, the circuit is simplified and the realizability is high, but also ideal demodulation of different types and frequencies of signals can be realized by adopting the low-pass filter.

The invention discloses an infrared lamp control module on basis of a 555 timer and an infrared camera. The infrared lamp control module on basis of the 555 timer comprises an infrared lamp control module and an infrared lamp module; and the infrared lamp control module is electrically connected with the infrared lamp module. The infrared lamp control module on basis of the 555 timer is characterized by also comprising a fine regulating module and a PWM (Pulse Width Modulation) signal generating module, wherein the fine regulating module is electrically connected with the PWM signal generating module; the PWM signal generating module is electrically connected with the infrared lamp control module; the PWM signal generating module comprises a resistance adjustable unit, an electric power storage unit and the 555 timer; the resistance adjustable unit is respectively and electrically connected with the electric power storage unit and the 555 timer to form a multivibrator; the fine regulating module comprises a knob switch; and the knob switch is electrically connected with the resistance adjustable unit. According to the invention, the brightness of an infrared lamp can be manually regulated according to the variation of the environment, the optimal night vision effect can be obtained, and meanwhile, cost of the infrared camera also can be saved.

The invention discloses a diode and triode testing circuit, a circuit board and a detector. The circuit comprises a power module, a selection module, a transistor protection module, a first 555 timer,a second 555 timer, a display module, a triode interface module and a diode interface module, wherein the fourth pin and the eighth pin of the first 555 timer and the fourth pin and the eighth pin ofthe second 555 timer are all connected with the power module; the second pin and the sixth pin of the first 555 timer are connected and then divided into two paths, wherein one path is connected withthe second pin and the sixth pin of the second 555 timer through a resistor R1, and the other path is connected with the ground through a capacitor C; the third pin of the first 555 timer and the second pin of the second 555 timer are connected to serve as a cathode of the diode interface module, and the third pin of the first 555 timer and the sixth pin of the second 555 timer are connected to serve as an emitter of the triode interface module; and the output end of the second 555 timer is connected with the selection module. The circuit has the advantage that it is convenient to test various states of diodes and triodes.

A starting-up control circuit is connected between a VGA (video graphics array) connector of a display and a super input and output chip on a mainboard and comprises a first electronic switch, a second electronic switch, a third electronic switch, a fourth electronic switch, a fifth electronic switch and a 555 timer, wherein when a power key of the display is pressed down, an address code pin of the VGA connector outputs a high level signal; a first end and a second end of the first electronic switch are connected with each other; a first end and a second end of the second electronic switch are connected with each other; a first end and a second end of the fourth electronic switch are also connected with each other; an output pin of the 555 timer outputs periodic pulse level; and when the output pin of the 555 timer outputs a high level signal, a first end and a second end of the third electronic switch are connected with each other, so that the super input and output chip receives a low level signal, and the mainboard is started. By using the starting-up control circuit, the mainboard can be started through the power key of the display.

The invention discloses a DC regulated power supply switch control method. The DC regulated power supply switch control method comprises the following steps: a manual switch is set to be a constantly-opened key switch and used for manual switch control; a control signal input end is set and is used for inputting automatic switching control signals; a 555 timer is set; the TH and / TL pins of the 555 timer are connected with the manual switch; the / RES pin is connected with the control signal input end; the OUT pin is connected with a clock pin of a D trigger; the D trigger is set; the D pin is directly connected with the / Q pin; the Q pin and / or the / Q pin is connected with a power control unit for outputting the switch control signals; the power control unit is set for the switch control according to the switch control signals from the D trigger. The regulated power supply control method can not only be controlled through external signals, but also can be manually controlled by the constantly-opened key; the invention has the simple circuit, the good stability and the high reliability.

The invention provides an intelligent control device for automatically detecting a vehicle speed and a vehicle spacing and relates to a control device capable of automatically detecting the vehicle speed and the vehicle spacing and automatically alarming if the vehicle speed or the vehicle spacing exceeds limits. The intelligent control device is provided with a speed detecting sensor CS, a spacing detecting sensor CJ and a detection and voice alarm circuit, wherein the speed detecting sensor CS is mounted on an automobile speed meter circuit; the spacing detecting sensor CJ is mounted on the front part of an automobile; the detection and voice alarm circuit is mounted on an electronic circuit board of an automobile control panel; and the detection and voice alarm circuit comprises a volt current condenser (VCC), adjustable resistors RT1-RT3, a OR gate OR, resistors R4-R6, capacitors C1-C3, a 555 timer chip, a relay K and a SPEAKER. Under the condition of mounting the speed detecting sensor and the spacing detecting sensor on the automobile, the detection and voice alarm circuit is used for detecting whether the automobile is at a safety speed and at a safety spacing and alarming if the speed and the spacing exceed safety ranges.

The invention relates to a motor running timing control circuit based on chips. The circuit comprises a five-pin toggle switch, a timing control circuit and a driving circuit, wherein the timing control circuit comprises a timer U2, capacitors C2, C3, C4 and C5, resistors R1, R3 and R5 and a slide resistor R5; the driving circuit comprises a chip U1, a triode Q1 and a diode D1. According to the motor running timing control circuit based on the chips, the timing control chip is a 555 timer, a control circuit in the motor current direction is formed by use of voltage change of pins 3 and 7 of the 555 timer, a motor driving chip is L9110S, has an H-bridge circuit inside and can drive a motor to rotate through larger current. Besides, by use of the reverse interception feature of the diode D1,a direction indicator lamp is rotated through the motor, and forward and reverse rotation of the motor can be observed directly.

The invention discloses an antitheft type light-operated circuit. The antitheft type light-operated circuit comprises a 555 timer, a phototriode T, a buzzer LB, an inductor L and a 6V power source U. A port 4 and a port 8 of the 555 timer are connected, the port 4 of the 555 timer is also connected with a collector of the phototriode T, an emitter of the phototriode T is connected with a port 7 of the 555 timer and a resistor R1, a port 2 and a port 6 of the 555 timer are connected with a slide rheostat R2, and the other end of the slide rheostat R2 is connected with the resistor R1. A capacitor C1 is connected between a port 1 and the port 2 of the 555 timer, the buzzer LB is connected between the port 1 and a port 3 of the 555 timer, and the 6V power source is connected between the port 1 and the port 8 of the 555 timer. The antitheft type light-operated circuit has the advantages of simplicity, low cost, high flexibility and good antitheft effect.