Main application range of thermistor and common role -
Knowledge of electrical resistance
This paper mainly introduces the main application range of thermistor and common function, this article word count 1088 words, read the full article 11 minutes.
Thermistor application range: induction cooker, electric pressure cooker, electric cooker, electric oven, disinfection cabinet, water dispensers, microwave oven, electric heating machine, industry, environmental protection, meteorology, food processing equipment and other household electrical appliances of temperature control and temperature detection and office automation equipment,
Such as photocopiers, printers)
, instrument coil, integrated circuits and quartz crystal oscillator and thermocouple temperature detection and temperature compensation.
Second, thermistor part 1, liquid level control puts two negative temperature coefficient thermistor container high and low level security position, applying fixed value and the heating current.
Thermistor in the immersed in a liquid at the bottom of the surface temperature of the same as the boundary temperature, at high exposure to the air thermistor temperature of the surface temperature is higher than the perimeter.
If the fluid level covered high resistance, make its surface overflow descend resistance increase, judging circuit resistance changes and timely notify the alarm device, can use action to cut off the circuit into the fluid pipe, surface protection effect.
If the liquid level drops to the bottom of the low, thermistor gradually exposed to the air, the surface temperature resistance drop, judging circuit can use resistance changes and inform action open circuit into the liquid line for liquid.
2, the temperature measurement for measuring temperature of thermistor generally has simple structure, low cost.
Because of its high value in itself, so negligible joint of contact resistance, and can be applied to the remote telemetry process thousands of meters away.
3, temperature compensation using negative temperature characteristic, can play a role of compensation in certain electronic devices.
When overload and make the current and the temperature increases, the thermistor resistance increase, reverse the drop-down current compensation, protection, etc.
At this time should be paid attention to thermal resistor should be concatenated in the electronic circuit.
4, temperature control in the mechanical and electrical protection and control, often will point thermistor concatenated in relay control circuit, when a device, in case of sudden failure overload caused by temperature.
If the tipping point resistance suddenly fell, the relay current exceeds action current rating and action, have cut off protection effect.
5 the function of protection, temperature of thermistor in some equipment management plays a key role, such as wireless phone, notebook computer, etc.
If the charging resistance being very high, these devices will soon complete charge of the battery.
But at the same time will also be in danger of overheating.
If the overheating temperature more than Curie temperature of the battery, the damage to the battery will not be able to recover.
But if the charging voltage is too low, the battery charging time will grow to the unbearable.
Using thermistors in the battery, can detect overheating resistance or batteries overheating, so as to adjust the speed of the charge.
As a result, when start charging the battery voltage will be big, so, in a short time can to the larger charging voltage quick charge.
And when will reach the critical voltage or critical temperature, can control the charging speed reduced, then, go more smoothly finish charging.
6, overheating protection, the size of the notebook computer is more and more small, the mainboard is very sensitive to temperature, the motherboard is very close to the heat source resistance, constantly improve the CPU frequency not only improves the speed of the CPU, its working temperature is high.
On this occasion, the surface encapsulation type thermistor can rapid response and overheat protection, also is easier to use.
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