Difference between active and passive transducer
A transducer is a kind of electrical or electronic device used to convert one form of energy into another energy form.
There are different examples for transducer which is capable of energy conversion, microphones, solar cell, filament bulb, and generator or motor.
The transducer is mainly categorized into two, active and passive transducer, in this article we try to explain the difference between active and passive transducers.
Active transducer VS Passive transducer
| Parameter | Active transducer | Passive transducer |
|---|---|---|
| Definition | Active transducer is called the self-generating transducer, an active transducer had the ability to convert one form of energy into another form without any external source | Passive transducer is called the externally energized transducer, a passive transducer converts a form of energy into another (electrical) by making use of an external source of power |
| Design | It had a simple design | It had a very complex design |
| Working operation | Operational energy is derived from quantity being measured | Operational energy is taken from an external power source |
| Output generation | Electrical current or voltage | Variations in quantity associated with passive elements are observed |
| Sensitivity or resolution | The smallest changes happen in the quantity will be easily detected, but it had a low resolution compared to the passive transducer | Passive transducers detect the smallest variation, it is more sensitive and accurate, and this is why passive transducers have higher resolution than active. |
| Signal conversion | Active transducer had the simpler signal conversion | The passive transducer had a complicated signal conversion |
| Energy production | The active transducer produces output from physical quantities | The passive transducer derive part of the power required the conversion from physical quantity under measurement |
| Output signal strength | The signal obtained from the active transducer have lower amplitude, so an amplifier is required at the output section | The output signal from the passive transducer did not require any amplification |
| Apps | Tachogenerator, thermo coupler, photovoltaic cell, piezoelectric crystal, and bourdon tube | Potentiometer, thermistor, linear variable differential transformer (LVDT), photomultiplier tube, and strain gauge |
Explain the key difference between the active and passive transducer
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Power source
The active and passive transducers are differed mainly due to the usage of power supply, an active transducer does not need any external power source to produce an output electrical signal, but a passive transducer needs an external power source for the output signal production.
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Transducer design
An active transducer had a simple design, this is because it had a self-energy generation capability and the passive transducer had a complex design due to multiple network arrangements.
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Working operation
The active transducer operating energy is been generated from the quantity that we measured, but the passive transducer needs an external power supply to operate.
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Output generation
The output of the active transducer is been generated as the variation of current and voltage, but a passive transducer variation happens on the quantity associated with the passive element is been observed.
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Sensitivity or resolution
The active transducer is more sensitive than the passive transducer, but the active transducer had low resolution or accuracy than the passive transducer, this is because the smallest bit of variations are been measured with the passive transducer network.
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Output signal strength
The output signal we obtained from the active transducer will have low amplitude and power, so we need to amplify the signal with a booster amplifier, but the output signal we get from the passive transducer does not need any amplification.
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Applications of transducer
The active transducer had the ability to convert non-electrical energy to electrical energy and this is the procedure to calculate the variations using an active transducer, e.g.: Tachogenerator, thermo coupler, photovoltaic cell, etc.
The passive transducer converts the non-electric energy variations to electrical energy using an external power supply, e.g.: potentiometer, thermistor, linear variable differential transformer (LVDT), etc.
