As we saw in the Operational Amplifier tutorial, the Operational Amplifier can be used to provide signal amplification when connected in inverted or non-inverted equipment.
The very small imitation signal voltage generated by the temperature sensor, such as a few millivolts or even picovolts, can be finally expanded many times by a simple arithmetic amplifier circuit, In order to generate a larger voltage signal, for example 5v or 5mA, it can then be used as a microprocessor or as an input signal according to the analog to digital system.
Therefore, in order to provide any useful signal, the output signal of the temperature sensor must be amplified by an amplifier, the voltage gain of the amplifier is up to 10,000, the current gain is up to 1,000,000, the signal The expansion is linear and the output signal is accurately reproduced. Input, just change the ups and downs. Then expansion is part of signal conditioning. Therefore, when using a simulated temperature sensor, before using the signal, it may generally require some method of expansion (gain), impedance matching, and the blocking between the input and output may require filtering (frequency selection), which can ultimately be calculated The amplifier is easily implemented. And, when measuring very small physical changes, the output signal of the temperature sensor may be "contaminated" by an undesired signal or voltage, and then obstruct the practical signal required for correct measurement. These unwanted signals are called "noise". By using the signal conditioning or filtering skills we reviewed in the ActiveFilter tutorial, you can reduce or even eliminate noise or disturbances.
Through the use of low-pass or high-pass or even band-pass filters, the "bandwidth" of noise can be better reduced, leaving only the desired output signal. For example, many types of inputs from switches, keyboards, or manual controls cannot quickly change conditions, so low-pass filters can be used normally. When the disturbance is at a specific frequency, such as the power supply frequency, a narrow-band push or notch filter can be used to generate the frequency selection filter.
Typical operational amplifier filter
after filtering For some random noise, it may be necessary to take a few samples and average them to get the final value, and then add the signal-to-noise ratio. Either way, under "practical international" conditions, expansion and filtering play an important role in connecting temperature sensors and transducers to systems based on microprocessors and electronic devices.
In a tutorial about temperature sensors, we will discuss the azimuth temperature sensor, which can measure the azimuth and / or displacement of a physical target, which is to some extent The above indicates the movement of a specific interval or viewpoint from one position to another.
