Uses
- Vibration measurements in industrial environments
- Permanent vibration monitoring on industrial machinery
- Airborne vibration monitoring on aircraft engines
- General vibration measurements with a measuring amplifier
| Features
- Small, rugged construction
- Suitable for both differential and single-ended output type transducers
- Sensitivity adjustable from 1 to 10 mV/pC
- Built-in high-pass filter
- Single or dual polarity power supply
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When the 2634 is used with normal, single ended transducers, the microplug adaptor JJ 0207 supplied allows the use of normal, low-noise coaxial cables; this adaptor automatically grounds one of the input poles.
The input amplifier is a differential charge amplifier consisting of a dual, low-noise FET and two, highgain IC operational amplifiers (Fig. 1). The lower limiting frequency of 1 Hz is determined by a filter network around the input amplifier which provides a 40 dB/decade fall-off in response over the decade 1 Hz to 0.1 Hz. This eliminates the influence of low frequency noise on the measured signal, for example due to the pyroelectric effects of some transducers in fluctuating temperature conditions.
The output amplifier has a low output impedance which is suitable for driving long cables. The influence of load capacitance on the high frequency response of the amplifier is shown in Fig. 2. By means of an internal 10 turn potentiometer, the gain of the amplifier can be adjusted between 0 and 20 dB.
In the interest of producing a rugged unit, the body of the Charge Amplifier is cast in aluminium alloy. The back plate, which is removable for access to the sensitivity adjustment potentiometer, is fitted with a rubber seal which protects the electronics by preventing the ingress of dirt, oil etc.
The Power Input and Signal Output of the 2634 is supplied with a 3.5 m long cable AO 0198 fitted with matching connector. Wherever possible power should be provided by a dual polarity supply with voltage between ± 6 and ± 24 V. This ensures that the output signal is centred at ground potential with negligible DC offset and that power supply noise and common mode signals ar more effectively suppressed.
When the 2634 is used with normal, single ended transducers, the microplug adaptor JJ 0207 supplied allows the use With single polarity power supplies, the output signal is DC offset to approximately + 6 V. Voltages of +...
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Product Data
