01-27-2015 11:54 AM
I have some random ultralow dc current signal from a sensor output and i want to convert this current to voltage by using integrator circuit.But I am getting difficulty in how,where and what to connect as a switch so that my integrating action should take place for 49 milliseconds and for one millisecond the capacitor should discharge for further integration.Like that for every 50 milliseconds my integrator should work.Please attach the circuit diagram.Answer is needed soon.
01-27-2015 02:26 PM - edited 01-27-2015 02:35 PM
01-27-2015 02:29 PM
The design of such a switch depends on the range of currents you are integrating and on the size of the integrating capacitor. The off-state leakage current of the switch should be much lower than the lowest input current. Of course the input bias current of the integrator circuit must also be low.
You may be able to use a simple FET switch or you may need a fairly sophisticated reset circuit, depending on your current range.
Will you be controlling the timing from the computer or will this be a hardware circuit?
Lynn
01-27-2015 02:30 PM
As usual, Henrik presents good ideas. I like the reed relay idea.
Lynn
01-27-2015 02:40 PM
01-28-2015 11:13 AM
Henrik AND Lynn:
As usual, BOTH of you have very good ideas and suggestions very often.
I look up to both of you. Wish I had kept my experience in electronics ongoing, it kinda got detoured . Wish I had more time to tinker around at home too!
-Pete