Electronic Components Datasheet Search |
|
AN4348 Datasheet(PDF) 5 Page - STMicroelectronics |
|
AN4348 Datasheet(HTML) 5 Page - STMicroelectronics |
5 / 25 page AN4348 Signal conditioning with a three-electrode sensor DocID025166 Rev 1 5/25 2 Signal conditioning with a three-electrode sensor To use a three-electrode sensor, a voltage has to be applied between the WE and the RE according to the specification of the sensor. The current generated on the WE has to be balanced by the electronics on the CE. No current should flow through the RE. A trans- impedance amplifier configuration is used to convert the current generated by the sensor into a voltage that can be read by the ADC of a microcontroller. This whole electronic design is called a potentiostat. Sensors are generally specified for a given resistive load which must be "seen" by the sensor. This value is generally in the range 10 Ω to 100 Ω. Figure 4 exhibits the main parts of the potentiostat circuitry. The U1 op-amp converts the current generated by the sensor into a voltage thanks to RT. The output voltage sensed by the ADC is then RT×Isense. Note that depending on the sensor (gas detected) this current can be either positive or negative (see Figure 2 and Figure 3). U1 also ensures that the sensor is loaded by the specified load (RL) and keeps the working electrode at a fixed potential. U2 fixes the specified voltage between the WE and the RE (VWE-VRE = -Vref). It also ensures that no current flows through the RE while providing the right amount of current to the CE to compensate the one on the WE. The microcontroller then computes the gas concentration from the reading made by its ADC as the gas concentration is proportional to Isense. Figure 4: Potentiostat principle |
Similar Part No. - AN4348 |
|
Similar Description - AN4348 |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.NET |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |