Sensors & transducers


Figure 3. LT6372-1 PGIA bridge interface with four gain settings.


total resistance seen between +RG,S and –RG,S. This is summarised as:


RF = 12.1kΩ + resistance between RG,F and RG,S on each of the two input amps


RG = Resistance between +RG,S and –RG,S


Gains from greater than 1V/V up to 1000V/V are possible with this configuration. With the switches set to short pins S3, and D3 on both U1 and U2 switches, here are the corresponding RF and RG values and the resulting gain:


RF = 12.1kΩ + 11kΩ + 1.1kΩ = 24.1kΩ RG = 73.2Ω + 97.6Ω + 73.2Ω = 244Ω


G = 1+ 2RF/RG = 1 + 2 × 24.1kΩ/244Ω = 199V/V


It is easy to see that deciding on which values to use for the external resistors is an iterative and interdependent process where the possible gain values interact and influence the choice of resistors to use. Some common gain value component values are tabulated in Table 1 for easy reference, but a multitude of other gain combinations (G) are also possible.


Instrumentation Monthly February 2026


Figure 4. LT6372-1 block diagram and simplified external connection (gain switches not shown) for the PGIA.


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