Voltage stabilization

[Ungi]

Hi,

I want to measure the voltage with PIC, I created the following circuit:


this is the signals,


I want to shift the output voltage, but unfortunately the shift voltage(green) is depending from the input(following the input). How can I stabilize this voltage, because I want 1.65V.

 

[mister_rf]

Use an adjustable Low Voltage Reference, example TL431 :grin:

or you need to recalculate resistors, in order to obtain the necessary results, see

 

[Syncopator]

The voltage at R8/R9 junction is being loaded.

You have R7 and R3, in series, from the junction of R8/R9, to earth via V6. Likewise V6 is loaded by the reference voltage circuit after R3.

To eliminate the problem, replace R7 with an op-amp voltage follower.

 

[mister_rf]

If we use a buffer need to keep the R7 in the circuit.
Also, same problems, R6/R7 (in the original circuit) need to adjusted down to 9.9K. :grin: