Chapter 1
Overview
21
The circuit forms a simple voltage divider. If one of the elements
changes value owing to an external stimulus, the output voltage will
also change. In practice, this configuration is not often used.
Half-bridge transducers will require adapting with compensating
resistors before use with a Bridge Amp.
Checking the Transducer
Before attempting to connect any transducer to a Bridge Amp, you
will need to determine the three things listed below. (This information
is normally supplied with the transducer; if not, you should consult
the manufacturer or supplier of the transducer.)
1. If the transducer requires an excitation voltage, and if so, what the
maximum excitation voltage, or recommended range, is for the
transducer.
2. The configuration of the transducer wiring connections.
3. If the transducer is a bridge-type transducer, and whether it has a
full-bridge or half-bridge configuration.
Transducers supplied by ADInstruments are supplied pre-adjusted,
and need no adjustment.
Do not attempt to connect the signal leads from the transducer to the
Bridge Amp if the wiring configuration is not known. Connecting an
incorrectly wired transducer to an excitation source is likely to
damage both the transducer and Bridge Amp.
positive excitation
positive excitation
negative excitation
negative excitation
Bridge elements —
resistors, thermistors,
capacitors, or a mixture
+
+
–
Figure 1–3
Left, a full-bridge
transducer; right, a half-
bridge transducer
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