Imagine you want to measure higher voltage using ADC of some MCU, such as that used in Arduino boards. Those are usually operating at 5V and can only read values in range of 0 - 5V.
So you create a voltage divider let's say with 100k Ohm on
Z1 and 10k on
From 0 up to 55V you will be getting 0-5V on
Vout so you are going to be able to reliably measure up to 55V. Problem is that anything higher than 55V on
Vin is going to result in output voltage higher than 5V on
Now if you connected say 80V power source to
Vin, you get 7.2V on
Vout - could this fry the MCU or would the impedance of voltage divider protect it by limiting the current that goes through? Is this safe to do?