Abstract: An electronic circuit for detecting a change in a property of interest, the circuit comprising a voltage detector having an input and a device for providing a bias current to the input of the voltage detector, wherein the circuit is arranged such that a change in the property of interest modifies the current received at the input of the voltage detector. A change in the property of interest may modify the current by adding or subtracting a current to the bias current. The property of interest may be a signal which is combined with the bias current thereby to alter the current at the input of the voltage detector. The signal may be capacitively coupled into the bias current. The signal may be provided by a sensor, which may be a voltage generating sensor and could be an antenna, rectenna, microphone or any other suitable sensor.

Abstract: An electronic circuit for detecting a change in a property of interest, the circuit comprising a voltage detector having an input and a device for providing a bias current to the input of the voltage detector, wherein the circuit is arranged such that a change in the property of interest modifies the current received at the input of the voltage detector. A change in the property of interest may modify the current by adding or subtracting a current to the bias current. The property of interest may be a signal which is combined with the bias current thereby to alter the current at the input of the voltage detector. The signal may be capacitively coupled into the bias current. The signal may be provided by a sensor, which may be a voltage generating sensor and could be an antenna, rectenna, microphone or any other suitable sensor.