Amplifiers are designed to enhance the electrical signal from the piezoelectric sensors and to transmit the amplified signal through a long coaxial cable to the measuring unit. Power to the amplifier is supplied through the same coaxial cable that carries the output signal. The length of coaxial cable can be up to 300 m.
The amplifiers are featured by extremely low noise. RMS noise at input is less 1uV.
All RANIS amplifiers have a bypass for transferring the test or calibration signal from the main unit to the sensor. The amplifier may be supplied with electric isolator and magnetic holder at the bottom of the enclosure.
3 types of compact amplifiers are now in production : RPA-04 for RANIS-10, RPA-05, RPA-07 for RANIS-11. In addition, the sensors with integral amplifiers are available.
RPA-05 and RPA-07 may be used as stand-alone. The output signal may be recorded with an oscilloscope or other system. The decoupling circuit for power supply is shown below.