Analog-to-Digital Converter – 555 (NI024E)

This circuit converts a resistance in the range between 1 k ohm and 1 MΩ to a signal in a frequency range which depends on C1 and R3. The square signal can be send to a remote reader by optic fiber, cable or other media. The circuit simulated bellow can be powered from 3 to 15 V supplies. In the simulation the transducer (R4) was replaced by a resistor.









To download the simulation files and Netlist - click here (

Circuit Bench