How does the Door Window Sensor malfunction detect?
Today we have to talk about the failure of doors and windows sensor detection: the current market, more types of doors and windows sensors, according to its structure and shape can be roughly divided into spherical, rod-shaped, tubular, round, The And then we are in accordance with the different heating methods can be divided into direct heating doors and windows sensors and side-by-side doors and windows sensors. At the same time in accordance with the working temperature range can be divided into room temperature, high temperature, ultra-low temperature thermistor. According to the temperature coefficient can be divided into positive temperature coefficient thermistor and negative temperature coefficient of doors and windows sensor.
(1) First of all, we look at the appearance of the doors and windows sensor. Potentiometer or Door Window Sensors must be marked clearly, the solder plate or pin without corrosion, rotary shaft rotation flexibility, elastic appropriate, rotating feel is smooth, and no mechanical noise and jitter phenomenon.
(2) the use of hand gently shake the potentiometer or Door Window Sensor pin, there should be no loose phenomenon.
(3) the multimeter resistance block to the appropriate range, and then we are in the ohm zero, and finally the use of two test leads (regardless of positive and negative) and resistors are connected at both ends of the pin, so that you can measure the actual Of the resistance value. Finally, the test value and the nominal value of the resistor to check, which can be a good judge whether the potentiometer or Door Window Sensor is intact. If the multimeter pointer is immobile, then it means that the internal resistor and disconnected.
(4) potentiometer or Door Window Sensor center pin and its internal active contact is connected. We use the multimeter of the two test tables were connected to the center of the pin and the rest of any of the pins, and then slowly rotate the shaft handle, the table pointer need to move accordingly, if the pointer has jump, drop the phenomenon, then the description The movable contact and the resistor are in poor contact.
Door Window Sensor is a resistance value will slowly change with the temperature changes in the sensitive components, it is within the operating temperature range, the resistance will slowly increase the temperature rise to increase the positive temperature coefficient (PTC) Door Window Sensors ; And the resistance value decreases with increasing temperature even if the negative temperature coefficient (NTC) doors and windows sensor. Here we talk about doors and windows sensors
One of the metal doors and windows sensor, its resistance will increase with the temperature and linear increase, while the resistance temperature coefficient of + 0.004K-1 or so. While the ordinary negative temperature coefficient of doors and windows sensors. Its resistance value will exponentially decrease with the increase of temperature, and the resistance temperature coefficient at room temperature is -0.02K-1 ~ -0.06K-1. Finally, even if the critical Door Window Sensor (CTR), its resistance value will be in a particular temperature near the temperature rise with the sharp decline, and his amount of change can reach 2 to 4 orders of magnitude. While curves 4A and 4B are barium titanate positive temperature coefficient window sensors. The former is a slow change, the temperature coefficient of resistance at room temperature is about between + 0.03 ~ +0.08K-1; and the latter is only switch type, so it will be in a small temperature range, the resistance value by several orders of magnitude , While the resistance temperature coefficient can reach +0.10 ~ +0.60 K-1.
The so-called Door Window Sensors, that is, a very sensitive for the temperature of the resistor. And this resistor in the temperature changes when its resistance will also change accordingly.
Currently the most widely used is the negative temperature coefficient of doors and windows sensors, but also can be divided into temperature measurement, regulator type, ordinary type.
In general, the nominal value of the Door Window Sensor is the resistance at ambient temperature of 25 ° C. When using a multimeter to measure its resistance, it does not necessarily match the nominal resistance. Here we simply to the positive temperature coefficient of doors and windows sensor as an example, simply talk about its characteristics, the temperature coefficient of the Door Window Sensors are also called PTC thermistor, the resistance of such resistors when the resistance value will also be followed Increase, while the change in resistance and temperature changes are proportional to the relationship, but the temperature of the resistor exceeds a fixed value, its resistance will increase dramatically, a file to increase to the maximum , Then the resistance value will slowly increase with the temperature began to decline.