A bidirectional sensor circuit includes a sensing impedance with first and second terminals; a first operational amplifier which non-inverting input is connected to the first terminal and its inverting input is connected to the second terminal; a second operational amplifier with the non-inverting input connected to the second terminal and its inverting input is connected to the first terminal; a first diode with the anode connected to the inverting input of the first operational amplifier and whose cathode is connected to the output of the first operational amplifier; and a second diode with the anode connected to the output of the first operational amplifier and to the cathode of the first diode. The input of the circuit consists of the terminals of the sensing impedance, and the output is at the anode of the second diode and senses a load impedance connected to the first terminal of the sensing impedance.