Which component of a digital panel meter converts analogue signals into a digital format?

1.) Analog to digital converter

• An analog-to-digital converter (also known as an ADC or an A/D converter) is an electronic circuit that measures a real-world signal (such as temperature, pressure, acceleration, and speed) and converts it to a digital representation of the signal.
• They first sample the signal, then quantify it to determine the resolution of the signal, and finally set binary values and send it to the system to read the digital signal.
• Successive Approximation, Dual slope, and Counter type are a few methods used for analog-to-digital conversion.

2.) Comparator

• A comparator circuit compares the input given at its input terminal and produces output according to the highest input.
• An OP-AMP working as a comparator produces +V_sat when input at the non-inverting terminal is greater than the inverting terminal.
• An OP-AMP produces -Vsat when input at the inverting terminal is greater than the non-inverting terminal.

3.) Magnetic field sensor

• Magnetic field sensors are devices that detect and measure magnetic fields around permanent magnets, current conductors, and electrical devices. 
• The working principle is based on the measurement of changes in the magnetic moment of magnetic material when exposed to magnetic fields.

4.) Hall sensor

• The hall effect sensor is a type of magnetic sensor which can be used for detecting the strength and direction of a magnetic field produced from a permanent magnet or an electromagnet with its output varying in proportion to the strength of the magnetic field being detected.