# Convert analog voltages to digital using 5 Volt 4bit ADC

Computer Science major here, I have some idea but not really sure about it.

I have a bunch of analog voltage readings. I need to convert them to digitized values (in volts). I am getting a 'Digital Value' through an online converter, which is in range 0 - 15. Assuming it has to do something with [2^4(bits) - 1 = 15]

Is there a formula to convert the 'Digital Value' into an output voltage (output through ADC)?
Some sample analog voltages: -4.3, 1.2, 3.1

• You should be able to derive the equation yourself - it's pretty straight forward. Your ADC's analog input is broken up into 16 equal voltage ranges. – mike65535 Sep 24 '18 at 1:14

$$\\displaystyle \frac{\textrm{Resolution of ADC}}{\textrm{System Voltage}}=\frac{\textrm{ADC Reading}}{\textrm{Measured voltage}}\$$
$$\ \displaystyle \frac{2^{10}-1}{5}=\frac{x}{2.12}\$$
Your ADC would read 434 once you solve for $$\x\$$. These types of numbers are good for microcontrollers like the Arduino that can read the voltage this way and you can make conditions based on the voltage it was reading, i.e. from sensors.