APCS the Signal Conditioning Specialists

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Input or signal powered transmitters derive operating power from the input signal which is conditioned and sent to the output load.

Input Powered

Input or Signal Powered Transmitters


The 0-5V output signal is derived from the measured variable. This represents a load on the measured signal. In the case of a high current CT this load is minimual.


4-20mA Input Powered

Input Powered Transmitters

The 4-20mA input signal powers the output drive.

Circuit loss is characteristic of input signal powered isolators. Two important factors to remember are;

  • Input drive voltage:
    The sensor or transmitter sending the signal to the isolator must be capable of producing more than 9.5V at 20mA output (480 ohm load maximum).

  • Output load range:
    The output of the isolator cannot drive into a load of greater than 250 ohms.

Because Signal powered isolators require no separate power supply, there is minimal effect on the wiring resulting in the lowest installed cost. As long as the input device has sufficient drive.