Technologies, Cell Phones
Proximity sensor: features and capabilities
In everyday life, the proximity sensor is used almost everywhere. On cars it helps with parking, on conveyors tracks the movement of products, in modern phones it blocks the keyboard after putting the device to your ear. In everyday life this miracle of technology also found its place. Such devices are installed in place of a switch, say, on the street. As soon as you come to the house, the light automatically turns on, and after a while it turns off. In security systems in general it is impossible to do without sensors.
There are proximity sensors by types: capacitive, inductive, optical, ultrasonic, microwave, magnetosensitive, pyrometric, etc. The kind of device that a particular device belongs to depends on the principle of its operation.
Capacitive sensors are also of several types:
1. Sensors on capacitors. It is the circuits of the latter that are a sensitive part of this device. This type is used where there is no need for noise immunity and high sensitivity, for example, in signaling devices that touch metal objects.
2. Capacitive sensors using a frequency-setting circuit. This type of device is less susceptible to radio interference and interference than devices with capacitors. This kind can be used in everyday life to turn on lighting, etc.
3. Differential-capacitive sensors. They differ from the above in that they have two antennas, and not one, which provides suppression of weather (rain, snow, thunderstorms, hoarfrost, etc.). Their field of application does not differ from the sensors on the LC-circuit. The only difference is that you need to install another antenna.
4. Resonance-capacitive sensors. The pickup signal occurs in the input circuit, which is in a partially unbalanced state with respect to the signal of the high-frequency generator. With it, the circuit is connected by means of a capacitor of small capacity (an element necessary for resistance in the circuit). Such sensors can be used both in field, rural, and urban environments, but not very close to powerful sources of radio signals.
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