I am currently working in a project that using a lot of foil strain gauges, but I only have one signal conditioner and one wheatstone bridge.
I heard that it is impossible to multiplex foil strain gauge, so I decided to use switches and turn it on-off alternately.
This is the circuit I imagine:
http://s3.amazonaws.com/data.tumblr...935950&Signature=FEmfFCRqcsZqbN7eC/Pp45ta2iI=
Since I need to turn it on-off rapidly (about 5KHz), I use optocoupler 4n25 instead of switch.
This is the circuit for 4n25
http://s3.amazonaws.com/data.tumblr...936251&Signature=nbAAtnnCM5htE9BO4/U8iJ/9J7g=
But somehow, it seems that 4n25 can't act as a switch properly (it cannot form short and open circuit at port 4 and 5). Did I make a mistake on using 4n25? and are there any other solution instead of using optocoupler as a switch?
I heard that it is impossible to multiplex foil strain gauge, so I decided to use switches and turn it on-off alternately.
This is the circuit I imagine:
http://s3.amazonaws.com/data.tumblr...935950&Signature=FEmfFCRqcsZqbN7eC/Pp45ta2iI=
Since I need to turn it on-off rapidly (about 5KHz), I use optocoupler 4n25 instead of switch.
This is the circuit for 4n25
http://s3.amazonaws.com/data.tumblr...936251&Signature=nbAAtnnCM5htE9BO4/U8iJ/9J7g=
But somehow, it seems that 4n25 can't act as a switch properly (it cannot form short and open circuit at port 4 and 5). Did I make a mistake on using 4n25? and are there any other solution instead of using optocoupler as a switch?