Products Mentioned

ADUCM355 Recommended for New Designs
The ADuCM355 is an on-chip system that controls and measures electrochemical sensors and biosensors. The ADuCM355 is an ultralow power, mixed-signal microcontroller...
Datasheet
ADUCM355 on Analog.com

Thread Details

  • State Not Answered
  • Replies 1 reply
  • Subscribers 4 subscribers
  • Views 282 views
  • Users 0 members are here
Options 

        

            Post
             Go back to editing
        

    

    


    

    









		


















	
	
			
	
			
		
	
	
		

	    
	    
	    		
Impedance measurement in EIS

		
	
				

			

									
					    HarshiniSenthil
					
							

            
            			
				
									
											
			
			
				
			
			
			    	
			                    
                
				                on Mar 5, 2025 
				
			
			
		

		
		                     
				
        		

		    
		    		    

		      		            		        
Category: Software

    		        		            		    
Product Number:  ADUCM355  

    		        		    		    

		    		    
		    			

			    
Hi ,


 I am working on M355_ECSns_EIS example.  For testing , 3  1K ohm resistors where connected in a star network and the resultant impedance shown was 1k in uart. Does this mean the evaluation board measures only one branch of star network ( between SE and star network midpoint) ? When 2K resistor was connected to SE and the midpoint of the star network, the impedance on uart was 2K Ohms. Could someone explain , what impedance ( between which points)  is actually measured ?

			

			
									
		                             
                        

    

                                            
                 software
                
                                                    
                 sensors
                
                                                    
                 Sensors and MEMS
                
                                                    
                 aducm355
                
                                                    
                 Electrochemical Sensors
                
                                
            

    
    
		


				
				        
        		

			
						
									
												
			
			
                        
                                    
                        
                        
                        
            
			            
						
						
			
			
			
			
		


        
        
        
    
					

			





















	

	

					



			


				
	









	
    
	

  • 
	
    



	
		
	
	



    
	
    
		
    
							
					
    
		
    
		    
		    		    
			
				
									
							        
			
			
			
    •  Analog Employees  
    
            
						
                            
            
            				
            
                on Jul 8, 2025 2:47 AM
            
            
						
			            		
    
		
										0
					
	
    

		
		
    
		
    
                                
                                                            
    
					
    Hallo  

    Yes the impedance between SE and Midpoint is measured. Thus is why you see also 2kOhm in the results, when you connect 2kOhm between SE and midpoint. Whereas other resistors are 1kOhm. By the way, in total there 4 resistors connected to CE,SE,RE and DE. As in Figure 22 of the EVAL-Board manual.
    

    For impedance measurement of a typical chemical sensor, you need a reference electrode (RE) as well as counting electrode (CE).
    Sensing electrode (SE) gives you the output of the sensor. 
    
			
    

		
			
	      

		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
						
				
						
				
				
		
		
    
			
		
    
	
    

    

    •