ADC and DAC
also: analog-to-digital converter · digital-to-analog converter · ENOB
Converters between the analog world and firmware: an ADC turns a voltage into a number; a DAC turns a number into a voltage.
Sensors such as thermistors, pressure transducers, current shunts and microphones produce voltages. An ADC samples them and outputs numbers the firmware can use. The key specifications are resolution (bits), sampling rate and accuracy. A 12-bit ADC divides its input range into 4,096 steps, but noise, reference-voltage error and board layout usually make the effective number of bits (ENOB) lower than the headline figure.
A DAC does the reverse, producing control voltages, audio or reference signals. Many products skip a dedicated DAC by filtering a PWM output instead.
Where it bites: the voltage reference, the analog front end (filtering, amplification, protection) and the PCB layout often matter more than the converter itself. Sampling without a suitable anti-aliasing filter lets high-frequency noise fold into the readings as false low-frequency signals.
Founder takeaway
Specify the accuracy you need at the system level, then check the reference, front end and layout, not only the converter's bit count.
sources
engineer review pending