How is a 3-wire combustible gas alarm connected to the measurement bridge circuit?
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Combustible gas detectors come in 4-wire and 3-wire versions. It’s easy to understand how the 4-wire version is connected in a bridge configuration; so, how is the 3-wire version connected to form a measurement bridge? It would be better if a diagram could be drawn. Thank you.
In a 3-wire system, the power negative terminal and the signal negative terminal should be shared.
This post was last edited by yuchenchf on 2016-8-2 at 14:21. Learned*
It seems that the sensing element used by the poster is a platinum element, and only resistance signals can be connected to the bridge. If the output is a resistance signal, you can think of the signal output and ground as a resistor, which constitutes one of the bridge arms of a bridge.