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With the development of science and technology, the progress of the society, the intelligence development of infants and young children more and more attention, all kinds of educational toys have mushroomed, emerge in endlessly, have electric, also have a electric, tens of thousands of its sort, quality requirements vary widely, uneven. When buying toys, people tend to think more about the playing function of toys, while neglecting the safety of toys. Many of the quality problems of toys are taken seriously by people in the event of an accident, but it is too late to cause harm to people, and some of them may be life-long. So how important it is to improve the safety of electric toys.
In foreign countries, especially developed countries, the most importance to the security of electronic toys, regardless of the certification testing, research and development design, customer requirements, etc., first consider security issues, followed by the function of the toys, electric toys, in particular, so toy safety protection is the primary problem.
In Europe and the United States "/ BS EN 50088:1996 international standard specified in clause 3.6.2 thermal cut-out: not by automatically disconnect circuit during normal operation or reduce the current limit toys or parts of the temperature of the device, the design for the user can't change its design value; In section 3.6.3, it is clear that the automatic recovery of thermal interrupts can be automatically restored after cooling of the relevant parts.
It is not difficult to see that the above mentioned keywords are "security protection", "hot break" and "automatic recovery of thermal interruption", all of which are the safety control problems of electric current heating of electric toys. It is the protection and control problem after the current and temperature.
In electric toys, electric motors, electric control board, power supply, battery, battery, transformers, charger), shell and parts, electric toys in the process of using, the improper use, often appear: motor blocked, the temperature of the motor and battery short-circuit fever, electronic control board on components of the damage caused by short circuit, battery charge discharge fever and so on. The electric toys can generate a large current in the circuit, causing the electric toys to appear in high temperature, combustion, battery explosion and other safety hazards.
Toys, over-current protection, had used glass fuse, temperature fuse, more insurance inductance, resistance and so on, but they are used at a time, need frequent replacement, can not complete the prescribed standards "automatic recovery thermal cut-out" function, and bad design will be counterproductive. A bimetallic thermostat is designed, but the bimetallic thermostat works only on temperature, and the thermal response is too slow, and the fault circuit is extended again when the power is switched off. In order to achieve the purpose of "automatic recovery of hot break", it is the best choice to apply "PPTC" for temperature and overcurrent protection.
PPTC also known as "self recovery fuse" or "fuse" ten thousand times, is the high sensitivity of nonlinear thermal resistor, when motor stalling or the current in the circuit is too large, PPTC leaping from low resistance state into a state of high resistance, thereby limiting motor or electric current of the circuit, have played an important role in protection in time. Only need single self recovery fuse (PPTC) device can be reached, the purpose of the over-current protection, not only can make electric toys, safe and reliable, through Europe and the United States safety certificate can reduce component costs, reduce the service cost, electric toys, vigorously improve the market competitiveness.
In electric toys, PPTC is usually selected as: R16, R30, etc., or SMD1812, SMD1210, SMD1206 and other patch series PPTC components.