1. Sensor classification;

 

2. Common types of accelerometers;

 

3. Selection index;

 

4. Selection principle.

 

Sensor classification

 

Two categories are mainly introduced here, one is active and passive, and the other is isolated and non-isolated.

 

Active sensors refer to sensors that convert non-electrical energy into electrical energy output, which only converts the energy itself, and does not convert the energy signal. It is also known as an energy-converting sensor or transducer. Therefore, this type of sensor requires external energy source excitation, such as excitation voltage, to work properly. Due to the need for energy conversion, electronic components are packaged inside the sensor, which will bring noise during the measurement process. Such sensors are ICP type (also known as IEPE type) acceleration sensor, zero frequency acceleration sensor and so on.

 

Passive sensors are sensors that can work normally without the need for an external power source, and can obtain unlimited energy from the outside. This type of sensor has no or minimal impact on the measurement system, such as strain gauges (flowers), piezoelectric sensors, and so on.

 

Isolation sensor refers to the isolation between the sensor and the structure under test, and current cannot flow between the two. Isolation sensors are electrically separated from the structure under test. For example, strain gauges (flowers) are usually isolated from the structure under test. The common practice for sensors to achieve isolation is to install an isolation device at the bottom of the sensor so that current cannot flow. As shown in Figure 1, the red device is the isolation device.