An Improved Strain Gauge Transducer Amplifier for Wind Tunnel Use
Neil Pollock · 1986
Abstract : An AC excited self-balancing instrument for measuring low level strain gauge transducer outputs is described. The design of a specific circuit optimised for use with a small wind tunnel force balances is presented with sufficient information to facilitate circuit optimisation for other applications. The instrument is intended for applications where the bridge output voltage is below the level that can be conveniently handled by conventional DC amplifier systems. Tests on a prototype instrument showed an input noise in a 0 .1 Hz t 0.7 Hz bandwith of 4 nV RMS, a zero drift of less than 0.1 microV per day and negligible sensitivity drifts. Keywords. Strain, Measuring, Instruments, Amplifiers, Wind tunnels, Strain gages.