In principle, electronic sensors are more precise than liquid or needle thermometers. You need to note however that electronic thermometers need more time to adapt to their environment than liquid thermometers.
Thus, with electronic appliances, the stability of the situation is guaranteed by taking correct measurements.
Don’t forget either that an electronic thermometer is more sensitive than traditional thermometers to sources of indirect heat, such as lights, projectors, wind heaters etc… A few centimetres apart, readings can therefore change by 1 or 2 degrees.

Air contains water vapour in variable quantities. The dew point is therefore the exact temperature measured when the convergence between the pressure, the temperature and the humidity lead to the condensation of the latter, to the point where it becomes liquid.

For example, with an air vapour content of 17,4 g/m², the dew point is 20°C. When the dew point is below 0°C, condensation occurs in the form of snow or ice.

The higher the dew point, the higher the air humidity is at a given temperature. We can also say the dew point temperature is the temperature at which air cools (at constant pressure and with a constant air vapour content) in order to reach saturation.
As a matter of fact, the state of saturation exists when air contains the maximum quantity of air vapour possible with temperature and humidity present.
The condensation of water vapour starts therefore when the air temperature is lowered to dew point (and beyond).