so I'm going 0..5v to 0..3.3.
Ive implemented a diode clamp , as per
1k, r3 , d3,d4 are bat 85 (schotty diodes)
it kind of works , but ive noticed the voltage range is 0..3.5v rather than 3.3v
Ive checked the voltage I'm feeding is 5.1v (from axo 5v line), and 3.28v (from vdda), this is according to my multimeter.
I also checked with 9v and again clamped from 0 to 3.51v
why the difference?
what does R1 do?
in this solution, my plan was to use a simple voltage divider to get the input, so theoretically, the clamp is needed in case I some how put more than 5v in.
(alternative opamp solution, I'm putting comments on below)
a couple of small related questions
- im assuming the circuit also needs the two grounds to be connected.
- if the dumb user (me ) accidentally puts a cv input from the modular to this, I'm assuming this is 'ok', just no current will flow. (vs output to output, where I'm assuming i should put a diode to protect reverse current)
EDIT: tried replacing diodes with 1N5818 and similar, clamps at 3.44v so still over the 3.28 Id expect.
apologies in advance if my terminology is incorrect, very much a noob on this stuff, please correct me where necessary, I'm keen to learn