Operating Principles of Common Gas Detector Sensors
1. The working principle of a universal proximity sensor:
The coil L in the oscillating circuit generates a high-frequency magnetic field. When the target object approaches the magnetic field, an induced current (eddy current) is generated in the target object due to electromagnetic induction. As the target object approaches the sensor, the induced current increases, causing an increase in the load in the oscillation circuit. Then, the oscillation weakens until it stops. Sensors use amplitude detection circuits to detect changes in oscillation states and output detection signals.
The degree of amplitude change varies with the type of target metal, therefore the detection distance also varies with the type of target metal.
2. The working principle of all metal sensors:
All metal sensors are basically of the high-frequency oscillation type. Like the regular type, it also has an oscillation circuit, in which the energy loss caused by the induced current flowing in the target object affects the oscillation frequency. When the target object approaches the sensor, regardless of the metal type of the target object, the oscillation frequency will increase. The sensor detects this change and outputs a detection signal.
3. Working principle of non-ferrous metal sensors:
Nonferrous metal sensors are basically of the high-frequency oscillation type. It has an oscillation circuit, in which the energy loss caused by the induced current flowing inside the target object affects the change in oscillation frequency. When non-ferrous metal targets such as aluminum or copper approach the sensor, the oscillation frequency increases; When black metal targets such as iron approach the sensor, the oscillation frequency decreases. If the oscillation frequency is higher than the reference frequency, the sensor outputs a signal.
4. Principle of proximity sensor:
Capacitive proximity sensors are composed of high-frequency oscillators and amplifiers, forming a connection between the detection surface of the sensor and the ground. They participate in the oscillation circuit and are initially in an oscillating state. When an object approaches the sensor detection face, the capacitance of the circuit changes, causing the high-frequency oscillator to oscillate. The two states of oscillation and stop oscillation are converted into electrical signals, which are then amplified and converted into binary switch signals.
