USES: * Field and laboratory measurement of vibration in terms acceleration, velocity and displacement together with piezoelectric accelerometer and voltmeter or measuring amplifier * Field recording of vibration and other signals together with portable tape recorders and level recorders « Underwater sound measurements with hydrophone * Mechanical impedance measurements FEATURES: • Charge Input ■ 3 digit conditioning to transducer sensitivity ■ Unified output ratings for simplified system calibration « High sensitivity up to 10 V/pC ■ Built-in integrators for displacement and velocity ■ Switchable low and high frequency limits ■ Built-in test oscillator The Charge Amplifier Type 2635 is a comprehensively equipped, charge conditioning amplifier intended for general vibration measurements with a piezoelectric accelerometer input and for underwater sound measurements in conjunction with piezoelectric hydrophones. Its output will be routed to portable tape recorders and level recorders, electronic voltmeters, measuring amplifiers and frequency analyzers. It can be powered from internal batteries or an external DC power supply and is equally suitable for portable use in the field and for general laboratory use. Description Reference is made to the block diagram shown in Fig.l. The 2635 is a four stage amplifier consisting of an input amplifier, low-pass filter-ampli-fier, integrator amplifier, and output amplifier. An overload detector, test oscillator and power supply unit are also included.