I have a voltage divider which is supposed to function as a crude input protection for an ADC (differential reading). I am familiar in calculating basic voltage dividers and this basically is just that, but somehow I am stuck now.
The ADC will see 0.24 volt since that is the differential voltage between the points A and B. But I am struggling to find the right equation to calculate the actual input voltage. Maybe someone is able to point me into the right direction.
Edit: I’ve been juggling with the formula a bit and it seems like I got my solution. So the voltage drop across R2 is supposed to be: UR2 = Uin * R2/(R1+R2+R3). Rearranging that formula will give me the input voltage.
I tried to verify that in practice and built a quick test-setup on a breadboard.
- Rtotal = 20.74 kOhm
- R2 = 0.9834 kOhm
- VR2 = 0.2372 Volt
The equation gives me 5.003V, opposing to 5.01V which I’ve fed into the circuit. But I guess that’s okay since I have to take some measurement error into account.