To quantify a physical entity, we need a device that converts the physical portion into energy that can be easily measured. To convert physical forces into measurable points, we use transducers. There are two types of transducers:
Active transducer
Passive transducer
An active transducer is a device that does not require an external power source to produce an output. It can convert a physical signal into a power signal on its own. This type of transducer has resulted in voltage and electrical signals.
Thermocouples applications range from home appliances to industrial processes, electric power generation, furnace monitoring and control, food and beverage processing, automotive sensors, aircraft engines, rockets, satellites, spacecraft, and many more.
A passive transducer is an externally powered transducer. This device cannot convert a physical signal into an electrical signal on its own to another energy source, the passive element. When connected, it transforms the motion by the fluctuations generated from the power source.
Temperature sensors are made of thermocouples. They are in everyday items like fire alarms, stoves, and refrigerators. They also measure temperature in digital thermometers and numerous automotive applications.
The key differences between active and passive transducers are explained in the table below:
Active | Passive |
It produces a voltage or current output without an external power supply. | It is a kind of transducer whose internal parameters include capacitance and resistance, which change when it comes in contact with a passive element. |
It has a more straightforward design. | It has a complex design. |
It has a low resolution. Therefore, the detection in output is shallow. | It has a high resolution and can detect small changes in output. |
The output depends on the signal which is used for measuring it. | The output depends on the signal from the external power supply. |
The working principle draws energy from the measured source. | The working principle draws power externally, which affects its physical properties. |
In conclusion, both types of transducers convert the physical forces into accessible, measurable energy depending on the situation.
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