Piezoelectric transducers (sensors) measure dynamic phenomenasuchaspressureand force. Thesephenomenacause stresses that "squeeze" a quantity of electric charge from piezoelectric material in the transducer (the term piezo means "squeeze" in Greek). The amount of charge \(q(t)\) is directly proportional to the measured variable \(x(t)\), that is \(q(t)=\alpha x(t)\). Signal amplification is needed because the amount of charge produced is on the order of pC. Figure P6-50 shows an OP AMP charge amplifier that provides the necessary gain. First, show that the OP AMP output is \(v_{\mathrm{O}}(t)=-K q(t)\). Then select a value of \(C\) so that the charge amplifier gain is \(K=5 \mathrm{mV} / \mathrm{pC}\).

Transcribed Image Text:

x(1) q(1) R C vo(1) 19