what is a transducer

Thread Starter


Joined Apr 3, 2009
my stepdad was working in a high voltage substation replacing monitoring equipment. knowing im into electronics he gave me this transducer. could someone please explain what this thing is and how it works? being a guy that likes to build things with stuff laying around, is there anything cool i can do with it? some type of project? ty!



Joined Feb 28, 2009
In general, any transducer is a device that will convert one type of energy into another. A microphone is a transducer that converts sound energy into an electrical format. A speaker is a transducer that will convert electrical energy into sound energy. It appears that the transducer you have is used to convert the combination of voltage and current to an analog signal representing wattage. The transformer tied to the line is either for isolation and possible voltage conversion to 120VAC. The current transformer is used to convert current being monitored into a voltage equivalent. The 120VAC shown at the bottom of the diagram provides power to the unit.


Joined Mar 6, 2009
A Warning if you are not a qualified electrician or technician:

I would strongly urge you not to try to connect this device to the AC mains or conduct any experiments with it powered from the AC mains - the risk of electrocution is too great when such things are done without the necessary skill or knowledge.

What is it?

Looks like a Hall Effect Multiplier transducer for determining the power consumption in a single phase AC circuit. The (hopefully) isolated DC output signal will be proportional to the real power draw from the supply side being monitored.

The markings suggest that with a 10k 'burden' on the DC output terminals [1,2] you would have a DC current of 1mA in the 10k when the AC power input at the transducer voltage [3,4] & current [5,6] terminals is 600W [120V and 5A]. The maximum ratings for direct connection inputs appear to be 120V AC and 5Amp AC - rms values.

You have the option of isolating the main [presumably higher] line voltage and line current values via a potential transformer for the line voltage and a current transformer for the line current. Suppose the AC line to line voltage was 1200V and the rated line current was 100A. With a 1200:120V isolation transformer for the voltage input and a 100:5A current transformer for the line current input you then have a power measuring capability of 600*10*20 or 120kW - being equivalent to 1mA into a 10kΩ burden resistance across the output terminals [1,2].

It appears that you might also need a 120V AC supply [9,12] to energize the unit itself to make it functional.

In summary interesting to look at but dangerous if used without the necessary knowledge & skill level.


Joined Mar 24, 2008
In general a transducer can go both ways. An antenna can transmute or receive. A speaker can also be a microphone. A piezo crystal can convert movement into electricity, electricity into movement, much like a speaker.